# Another auto-reverser question or two



## CliffyJ (Apr 29, 2009)

Hi,

I've got a main line in the shape of the letter 'wye', with each of its ends having a reversing loop. By "wye," it's just that shape; it isn't a reversing wye. No track laid yet, still working on the roadbed, but I want to make sure I have all the bits and pieces.

The DCC system is 10-amp NCE.
The switch machines are ProDrive DC/DCC (from Train-Li): "a slow motion switch drive with integrated electronic controller. "
Preferred auto-reverse module is DCC Specialties PSX-AR (thanks Greg for the reminder!).

1. Is the (motor-driven) ProDrive the same as the "stall motor" (in DCCS lit) that the PSX-AR is supposed to handle? Or am I confusing "stall motor" with something else?

2. I'm only going to be running 2 (or maybe 3) trains at a time, eventually. But for this year and probably the next, just 1. So maybe I can wait to add PSX circuit breakers (to manage the 'wye' in 3 districts). Or is there some reason I need to add them now? 

3. Per the Kevin Strong article, does the PSX-AR avoid the problems of pitting the rails and tires (due to switching polarity only after the train causes a short)?

4. Anything else I should be concerned about here?

Thanks!

Cliff


----------



## Greg Elmassian (Jan 3, 2008)

1. Stall means that power is constantly applied. I think the ProDrive motors will accomodate this, but check with Axel. 

2. Adding circuit breakers is just insurance against damage to a loco in certain short circuit conditions. Just like insurance, do without it and you take your chances. Pay attention to your locos and don't let them sit if you have a derailment. Since you have an NCE system, 3 presses on the red button cuts all track power instantly. 

3. I have this type of breaker as well as many other people. I've never heard or seen excessive pitting of wheels, and certainly not rail from this type of operation. Please consult other DCC users with years of experience yourself to see what they think. I'm experienced, my opinion and my track and wheels say that it's not an issue. 

4. Nope, unless you want to run right up next to 10 amps ALL the time, then you want to add the heat sinks, as the manual states. You can get them from Tony's Trains. I have them and the sonalert that beeps when you have a short. 

Greg


----------



## CliffyJ (Apr 29, 2009)

Hi Greg, 

Thanks, you've answer all my questions! 

Yeah, I saw mention of the heat sinks in the manual, but didn't quite understand when they're needed; and you just clarified that. 

Sounds like I should design the 3 legs of the main line "wye" as power districts, each protected by the breaker, because they each represent opportunity for independant train operation. If I'm understand the purpose in making "districts". 

Question, I thought the NCE booster had its own breaker circuit? If so, is it as adequate as the PSX? If yes, and since I'll only get to the first leg (& district) of the "wye" this season, should I still employ the (single) PSX? 

Another one. Does the alarm sound off, every time the train wheels trigger the AR unit? Or only in actual short conditions? Didn't see that in the manual. If the former, it might be annoying; if the latter, it sounds like a great debugging tool. 

Thanks once again! 
Cliff


----------



## Greg Elmassian (Jan 3, 2008)

Ahh, you make the wye all one power district and run from the PSX-AR (it not only is an autoreverser, but a circuit breaker)... 

The NCE has it's own breaker, but it trips at a very high current, way over 10 amps... the PSX is completely programmable with jumpers and/or DCC commands from 1.27 amps to about 19.7 ... 

The alarm sounds when there is a short, and the power is interrupted to the autoreverser output. The breaker and the sound reset after the short is removed... it's actually way more sophisticated than that internally, but it just works great... did you look at the manual? It has a feature list up front. 

Did we have a drawing of your wye? The wiring is pretty simple, and you can also wire it several ways, depending on which part of the wye is the "mainline". 

Regards, Greg


----------



## chuck n (Jan 2, 2008)

I don't run DCC, but I do run straight DC. Since both get power from the rails, this may be applicable. I have engines from several different manufacturers, LGB (many), USAt (Diesels), Bachmann (spectrum) and Aristo (mallet and mikado). The only engines that I have trouble with pitting on the wheels are the LGB European Mallet, Uintah and Sumpter Valley Mallets. I When running at night I have seen sparks where the wheels contact the rail. These engines all have two motors and for some design reason may draw more current that any of my other two motor engines. These Mallets really require clean wheels and track. This has never been a problem with any other of my engines, whether they have one or two motors. I have to clean the wheels on those mallets much more frequently than any other engines. These engines, do not have power pickup skates, that may be the difference between these and other LGB engines. The Bachmann and Aristo steamers, do not have skates and they don't pit.


Come to think about it I remember that the LGB Zillertal tank engine doesn't have skates and I have had problems with pitting on that one also. It also requires more wheel cleaning than other engines. 


I don't think that pitting is something that you really have to worry about, but if you suspect pitting on a locomotive, keep the wheels and track clean. 


Chuck


----------



## Greg Elmassian (Jan 3, 2008)

Pitting of wheels is usually a number of things, usually from small arcs from the current flowing. The bottom line is that the normal arcing and wear caused by running track power is happening all the time, and any extra from an autoreverser is trivial. 

One interesting thing discovered quite a long time ago by George Schreyer, is the often overlooked motor resistance. Extremely low resistance motors can draw huge amounts of current in a way such that the average current looks ok, but the transients are much higher in current, and promote pitting much faster, i.e. the typical example of USA trains Geeps... 

The solution is simple, a low ohm resistor in series with the motor... only a little lost in top speed, but a significant reduction in "inrush current", and reduction in pitting of wheels. See his site for more. 


I have SS rail, which seems to have more arcing between the wheels and rails than brass, and there's no extra wear at the rails at my wye, nor more significant pitting for the locos that frequent that area. 

Greg


----------



## CliffyJ (Apr 29, 2009)

Thanks Chuck, that's good background on the "pitting" issue.
Regards,
Cliff


----------



## CliffyJ (Apr 29, 2009)

... and any extra from an autoreverser is trivial. 

Music to my ears! 

Apparently, Kevin in his article was referring to higher-amp-triggering solutions, and the Massoth unit (which he was reviewing) and, apparently, this one from DCC Specialties, don't have that as an issue. I tried to find the ref and article, but no joy. 

But whatever; you've settled the matter, so thanks!

I don't have a simplified schematic (should do that) of the layout, but for these purposes, it's just the letter "wye" (no 'bridging' track across the crotch; just a simple 2-pronged fork), each of the three ends having a return loop. The main line is the "wye", and has all kinds of spurs and sidings in each of its three legs. Two of the loops have spurs coming off them.

From the DCCS lit, it appears that I need a PSX-AR for each of the three rev loops. 

And I'm hoping that their "stall motor" output works with the Proline switch machines; the latter has a motor and limit switches, from what I can tell. I put the question to Axel yesterday morning, and also to DCCS, for confirmation. But it sounds like they'll go together ok. 

Thanks again Greg,
===Cliff


----------



## Greg Elmassian (Jan 3, 2008)

I think you will be fine... also a new feature in the PSX-AR is the "double reverse" feature, where if you have a reverse loop connected to another, in the old days, the 2 autoreversers could "fight", but the latest version has a special feature to handle this. 

Greg


----------



## Axel Tillmann (Jan 10, 2008)

The ProDrive und DCC is always connected to power, that how it receives the commands. In analog mode it needs 1-4 seconds of power (depending on the configuration) but works also with constant power since the electronic works in limiter mode.


----------



## CliffyJ (Apr 29, 2009)

Hello Axel!

It sounds like you are saying that the PSX-AR unit will indeed work with the ProDrive; that's great confirmation, and thank you. Question, would you have recommended something else for controlling reverse loops?

===Cliff


----------



## CliffyJ (Apr 29, 2009)

Well, Larry Maier (of DCC Specialities) got back with me, and said: 

"The PSX series will not work with the ProDrive. You only need a simple Tortoise slow motion switch machine to make it work." 

I responded to him that the ProDrives allow for a constant triggering power feed, and that the Tortoise seems not as specialized as the ProDrive for outdoor / G-gauge implentation. I'm awaiting his response; but does anyone have a clarification here? I've already obtained the ProDrives from Axel, and am sold on their reliability outdoors (and operability via DCC, and applicability to G-gauge). Not so sure about the Tortoise. I've also ordered the PSX-AR's, so I'm hoping for the best...

Regards, 
Cliff


----------



## Greg Elmassian (Jan 3, 2008)

Larry was probably unaware that the prodrive has a DC mode, he saw the DCC compatible part and got confused. 

Axel and I are right... if you want the PSX-AR to automatically throw the switch, then you set it up in DC mode.. if you are controlling it by DCC, then you set the DCC address... what you cannot do is control it with DC AND DCC at the same time, you need to choose. 

My understanding was that you wanted the PSX-AR to throw the turnout for you... this it can do... 

Greg


----------



## CliffyJ (Apr 29, 2009)

Huh. Well, I guess I was assuming I could throw the turnout one way or the other via DCC command, and that the AR unit would throw it the other way (at a certain threshold that I don't understand yet). 

But I'm ok with DC-only, e.g., having a default switch position hard-wired in...? I'm confused... 

But thanks for the continuing education! 

Cliff


----------



## krs (Feb 29, 2008)

Posted By CliffyJ on 24 Aug 2011 05:15 PM 
Huh. Well, I guess I was assuming I could throw the turnout one way or the other via DCC command, and that the AR unit would throw it the other way (at a certain threshold that I don't understand yet). 

But I'm ok with DC-only, e.g., having a default switch position hard-wired in...? I'm confused... 



Cliff,

I find the instructions extremely confusing - even if one is very faminiar with electronics.
They really need a rewrite.
But from what I read in the instructions, you can actually do either - throw the turnout one way or the other via DCC command or use two pushbuttons, one for each direction, to throw the turnout that way (explained on page 11 of the instructions).


What I think may be a consideration is the distance between the turnout and the gaps in the reverse loop - seems to me that distance must be longer than the longest train to make sure the turnout doesn't get thrown automatically before the last car clears the turnout.
I'm also not sure how the unit handles a train backing up through the reverse loop if all the cars have plastic wheels. Similar situation where the distance between turnout and rail gaps is important.

Knut


----------



## Greg Elmassian (Jan 3, 2008)

Yep, you found what I wanted you to find. 

The Prodrive can be in EITHER DC mode or DCC mode, not both... so you have to pick one... if you want it thrown automatically from the autoreverser, then you need to set it up for DC mode only. 

Now the autoreverser will throw the turnout, and you can hook up a couple of pushbuttons to the autoreverser to allow manual control of the turnout. 

Axel should come in here and confirm my statement about the Prodrive being set DC or DCC... 

Put metal wheels on the last car of the train... 

Greg


----------



## Axel Tillmann (Jan 10, 2008)

Yes, ProDrive can only be either or. Settting it up for DC disables the DCC command interface, except for the programming. But the user guide of the reverser has a DCC accessory interface module which allows you to addresss the ProDrive still through DCC.


----------



## CliffyJ (Apr 29, 2009)

Posted By Axel Tillmann on 25 Aug 2011 01:10 AM 
Yes, ProDrive can only be either or. Settting it up for DC disables the DCC command interface, except for the programming. But the user guide of the reverser has a DCC accessory interface module which allows you to addresss the ProDrive still through DCC.

Very interesting, thanks Axel. I'll look for that, when the unit & manual arrive in the mail.

I'm hoping that I don't have to run a seperate DC feed for this... especially since both the reverser unit and ProDrive would have been directly powered off the DCC rail bus. But what the heck; no matter how hard this may be to resolve, it'll be vastly easier that the concrete roadbed I've been tryin' to lay! 

Cliff


----------



## Greg Elmassian (Jan 3, 2008)

No, the unit is track powered... and it will source the power for the prodrive.. 

No extra wires... 

Greg


----------



## Axel Tillmann (Jan 10, 2008)

In an ideal world, you would only connect the ProDrive to the track and the auto-reverser to the track, but that would require that the auto-reverser sents DCC commands to the drive. Unfortunately the autoreverser can only send DC power to the drive. Depending on where you store the autoreverser this can be quite some cable. There is in this case an easier way.

ProDrive has two input triggers. you can have a small insulated rail section (1/4") in one rail and the wheel going over it make conenct from the rail power to that insualted section and voila, the drvies moves automatically to the new positon. Needless to say that that insulated section needs to be that far into the loop that the entire train has cleared the switch in question, which come to thnk of it, might be actaully tricky with the reversing loop controlling it.

The second trigger needs to be that far into the track leading up to the reversing loop that the entire trains has alredy passed and cleared the switch before the switch is switched back. The other possibility is that the loop is big enough to put both triggers in. in that case the entire train needs to fit inbetween the two trigger points.

Again I am now raising the question how a single segment reversing loop would switch the switch AFTER all the cars have passed? The only way I can see that happening is when the reversing loop is 3x train length, with the cetner section being feed by the reversing loop.


----------



## CliffyJ (Apr 29, 2009)

Posted By Greg Elmassian on 25 Aug 2011 04:59 PM 
No, the unit is track powered... and it will source the power for the prodrive.. 

No extra wires... 

Greg Good news, thanks Greg. Sounds like you've used this combo before?


----------



## CliffyJ (Apr 29, 2009)

What happens with a train having a mix of metal and plastic wheels? Nothing?


----------



## Greg Elmassian (Jan 3, 2008)

The autoreverser works by detecting non-matching polarity... metal wheels will bridge the insulated gap and cause it to operate and reverse polarity if needed. 

Plastic wheels will not have it sense anything... so no changes until a metal wheel hits.. 

Greg


----------



## CliffyJ (Apr 29, 2009)

OK, let's see if I can put this in terms I can comprehend. Bear with me, Greg; you have so many times, and I thank you! But here goes.

Let's say the switch is thrown to the right, but the loop isn't aligned in polarity for that direction. 

The first pair of metal wheels to bridge that insulated gap will cause the AR module to sense the short, and immediately reverses the loop's polarity.

Polarity will now be in line with switch position. 

Train moves thru; and subsequent metal wheel pairs (including the drivers of the loco, assuming any leading wheels performed the triggering) merely add an additional trigger to the AR module; but since all is already ok, those triggers are ignored (that is, already satisfied, re. loop polarity and switch alignment).

On the other end of the loop, another isolated gap is encountered. The train is completely in the loop; but the main line polarity is now wrong. 

Again, the lead wheels of the loco are first to bridge the gap. A short is sensed, and... then what? 

-- I guess that somehow the AR module forces a reversal in mainline track polarity? Must do; but I don't see that (yet) in the DCCS diagrams / info.
-- That reversal of mainline polarity hoses the direction of any locos than might have been sharing the main line, yes? 
-- There seems to be a serious timing issue here. If the train (in the loop) is traveling at full speed, the "exiting" insulated gap must be placed at a sufficient distance from the turnout so that when the AR module "sees" the discontinuity and attempts to throw the switch, there is sufficient time for the switch machine to do its job. So, though the DCCS diagrams imply those gaps to be placed just at "prongs" of the switch, perhaps they should be placed, say 3 feet, before entering said "prongs" (sorry for my lack of the proper term), in order for the switch machine to have sufficient time to react?

Educate me people, I'm poking in the dark here.

Thanks Greg, and everyone,

===Cliff


----------



## Axel Tillmann (Jan 10, 2008)

Cliff:
"....must be placed with sufficient distance...." My point of the earlier post. If oyu want to be direction independant and utilize the throw feature you loop needs to be three times the maximimum train length and the insulated section is smack in the center.

In terms what happens with an autoreverser?

No the autoreverser only changes the polarity of the insualted section, never the polarity of the main line. Since changing the polarity only influences which wires go where (so to speak) and have 0 directional influence it really doesn't matter where you would change the polarity. But it only makes sense in the loop otherwise you need an autroreverser as powerful as your central station.

But what matters is how fast the unit is.


----------



## krs (Feb 29, 2008)

If the auto-reverser controls the turnout, then the location of the rail gaps becomes important.

Maybe a drawing will help:










Cliff,

From the diagram you can see that the auto-reverser will only affect the polarity of the isolated section in the reverse loop, that's what the output ois connected to.
The main line just provides the input.


However, if the auto-reverser controls the turnout as well as the manual controls, there are some specific considerations.
In the above diagram - if the turnout has been set manually to the right, will the auto-reverser be smart enough to recognize that when the loco wheels hit the first rail gap and reverse the loop polarity without throwing the turnout in the opposite direction since at that time all of the train hasn't cleared the turnout yet?

Or does one need to move the rail gap from the approximate location show in the PSX-AR instructions so that the distance between turnout and rail gap is greater than the longest train.

Same thing would apply to the top rail gap.

The other consideration is the time it takes to throw the turnout when you use the proswitch.

As Axel said, you need a pretty long reverse loop from what I can see.
I always hate things I have to set up taking the longest train into account.


Knut


----------



## CliffyJ (Apr 29, 2009)

Thanks Axel and Knut. 

But when & how does the main line polarity change, when the train exits the loop? 

I think I've been missing something fundamental here. I was vaguely assuming that one train could go back and forth across the layout, reversing in the loops at either end. But now that I think about it, that would require a mainline polarity change, with each loop exit; and that would interfere with any other loco operating on a side track. Ugh...

===Cliff


----------



## rdamurphy (Jan 3, 2008)

It doesn't CliffyJ. The direction of a DCC controlled locomotive is set by the Decoder, NOT the track polarity. Think about it, you're moving forward, you stop, and reverse, the track polarity stays the same. The Decoder reverses the polarity to the motor. According to the DCC Tutorial ( http://www.dccwiki.com/DCC_Tutorial_(Power) ) the track power isn't even DC, but a "special form of AC". 

So, why reverse the polarity at all? Simple, if you didn't, when a locomotive, lighted car, or even a wheelset, bridged the gap, you'd have a direct short. Hence the reason for the "longest train" rule. You don't want your lighted caboose at the end of the train to short out the layout when it crosses the gaps. Train length wouldn't matter if all of the wheelsets were plastic - and if you never ran any lighted cars or rear train helpers. 

Robert


----------



## CliffyJ (Apr 29, 2009)

I get it! Duh!!

Must have geezing back to old HO memories, and thereby confusing everything, sorry about that guys. 

So I guess what we've been discussing has not only to do with this anti-shorting issue, but when the turnout gets thrown, hence Axel's and Knut's ideas, which I will now re-read. 

Thanks Robert!


----------



## CliffyJ (Apr 29, 2009)

OK, now it's clear to me what Axel & Knut were saying about the loop needing to be 3X the train length. That's probably the surest way to go. But how about one more scenario. 

1. The PSX-AR reverser, since it controls the ProDrive, is "thrown" one way or the other; so both loop polarity and turnout position must be in sync. 
2. In crossing the first (entering) gap, nothing needs to be done. Metal wheels (first and last) don't cause anything to happen.
3. In crossing the second (exiting) gap, that's when the AR unit flips polarity and turnout alignment. Both are still in sync. 

Am I getting it finally? 

If so, the insulated section ("loop length") needs to be 1X max train length; and the distance between each gap and the turnout is a function of how fast the ProDrive flips the switch position (vs. max train velocity). Call it "response length." If this logic works, the train length might be much longer, e.g., TL = LL-(2 x RL), as opposed to TL = LL/3.

Anyone concur?

The remaining matter is that of triggering the AR unit, perhaps via the pushbuttons described in the manual and mentioned by Knut. But I'd rather not mess with local controls for now. So to get back to DCC operation of the turnout, I suppose that those button inputs could be replaced with a stationary decoder, and perhaps a relay? 

Now, suppose the loop has a default position. Yes, I could just use a spring and forget the ProDrive. But per past threads, lightweight cars (such as the ore car strings I'm going to be running) won't always force their way thru, and are therefore subject to derailment. Could the above described control approach be simplified in some way?

Thanks everyone, 
===Cliff 

[My apologies, I edited this while Knut and Axel were responding to what I'd written prior]


----------



## krs (Feb 29, 2008)

Cliff - 

Yes, you're getting it - almost. 

But re your statement: 
If this works, the train can be much longer (vs. loop length). 

If the train has metal wheels on any of the cars, those will have to be inside the isolated part of the loop controlled by the auto-reverser. 
Greg earlier suggested putting metal wheels on the last car so everything works if you ever back up through the reversing loop, in that case the train can't be any longer than the isolated part of the loop. 

Knut


----------



## Axel Tillmann (Jan 10, 2008)

OK, now it's clear to me what Axel & Knut were saying about the loop needing to be 3X the train length. That's probably the surest way to go. But how about one more scenario. 

1. The reverser, since it controls the ProDrive, is thrown one way or the other; and both polarity and switch are in alignment. 
2. In crossing the first (entering) gap, nothing needs to be done. 
3. In crossing the second (exiting) gap, that's when the AR unit flips polarity and switch alignment. 

In this case, the insulated needs to be 1X train length; and the distance between each gap and the turnout is a function of how fast the ProDrive flips the switch position (vs. train velocity). If this works, the train can be much longer (vs. loop length). 

Am I getting it finally? 

So now, it's a matter of triggering the AR unit, perhaps via the push buttons described in the manual. But to get back to DCC operation of the turnout, I suppose that those button inputs could be replaced with a stationary decoder, and perhaps a relay? 

Thanks everyone, 
===Cliff

1. The reverser, since it controls the ProDrive, is thrown one way or the other; and both polarity and switch are in alignment. 
Kind of. and not so. Here is the problem, switch and polarity should not be viewed as being connected to each other. Why? 
Let's define the switch can be either set for straight or curved. The switches position can be set independently (via DCC command) from anything else. Therefor if you prefer to go over the straight into the loop and therefore set the switch to stragiht (after you exited the loop out of the curved position) then your loop has the wrong polarity the next time you go straight again. For a reversing loop not a big deal. But for a reversing loop that effects the switches position every single time, it definitely might be.

2. In crossing the first (entering) gap, nothing needs to be done. 
That depends on the switches position. This statement is only true if you enter the loop the way you last exited the loop.

3. In crossing the second (exiting) gap, that's when the AR unit flips polarity and switch alignment. 
Yes there will be always a reaction by the AR on the second gap. However it is unclear to me if the AR will always switch the switch and what it wll do to the switch. Why do I say this? Because I don't know what happend if you switch the switch via a DCC command in the meantime. That's why I said in worst case scenario you need 3 train length, because the entire train needs to be out of "harms" way if you cross any gap, so that the AR can do what it want with the switch position without derailing parts of the train. However, do to not knowing how the AR does the sequencing of the switch movement, I am not quite clear if on the next gap you might end up with the wrong switch position.

But as I mentioned before..... the "idiot" proof method is to operate ProDrive in DCC mode and use its trigger function. That will always work in a predictable fashion.


----------



## CliffyJ (Apr 29, 2009)

Posted By krs on 27 Aug 2011 12:21 PM 
Cliff - 

Yes, you're getting it - almost. 

But re your statement: 
If this works, the train can be much longer (vs. loop length).

If the train has metal wheels on any of the cars, those will have to be inside the isolated part of the loop controlled by the auto-reverser. 
Greg earlier suggested putting metal wheels on the last car so everything works if you ever back up through the reversing loop, in that case the train can't be any longer than the isolated part of the loop. 

Knut 
Thanks Knut (and Greg). That makes total sense. I.e., it the loco has triggered the AR to "throw" both polarity and turnout, but you change your mind just after that point and decide to back out, yeah, you'd be counting on the wheels of the last car to reverse your decision. But if the loco hadn't triggered that "throw" (via the second gap), everything is still in alignment to back out anyway. Does that sound correct? 

===Cliff


----------



## CliffyJ (Apr 29, 2009)

Posted By Axel Tillmann on 27 Aug 2011 12:46 PM 

1. The reverser, since it controls the ProDrive, is thrown one way or the other; and both polarity and switch are in alignment. 
Kind of. and not so. Here is the problem, switch and polarity should not be viewed as being connected to each other. Why? 
Let's define the switch can be either set for straight or curved. The switches position can be set independently (via DCC command) from anything else. Therefor if you prefer to go over the straight into the loop and therefore set the switch to stragiht (after you exited the loop out of the curved position) then your loop has the wrong polarity the next time you go straight again. For a reversing loop not a big deal. But for a reversing loop that effects the switches position every single time, it definitely might be.

2. In crossing the first (entering) gap, nothing needs to be done. 
That depends on the switches position. This statement is only true if you enter the loop the way you last exited the loop.

3. In crossing the second (exiting) gap, that's when the AR unit flips polarity and switch alignment. 
Yes there will be always a reaction by the AR on the second gap. However it is unclear to me if the AR will always switch the switch and what it wll do to the switch. Why do I say this? Because I don't know what happend if you switch the switch via a DCC command in the meantime. That's why I said in worst case scenario you need 3 train length, because the entire train needs to be out of "harms" way if you cross any gap, so that the AR can do what it want with the switch position without derailing parts of the train. However, do to not knowing how the AR does the sequencing of the switch movement, I am not quite clear if on the next gap you might end up with the wrong switch position.

But as I mentioned before..... the "idiot" proof method is to operate ProDrive in DCC mode and use its trigger function. That will always work in a predictable fashion.
Hi Axel,

I've been assuming that the AR unit has control over the turnout (via the ProDrive), and that any change in turnout position must be made thru the AR unit -- thus assuring them being in sync. Would that satisfy things?

I apologise, I was editing (and amplifying) my prior email when you were posting...

What you say lastly is interesting though, but I don't understand this "trigger function." I'll have to re-read again!

Learning more by the hour...

===Cliff


----------



## CliffyJ (Apr 29, 2009)

Posted By Axel Tillmann on 25 Aug 2011 01:10 AM 
Yes, ProDrive can only be either or. Settting it up for DC disables the DCC command interface, except for the programming. But the user guide of the reverser has a DCC accessory interface module which allows you to addresss the ProDrive still through DCC.
This must be what you refer to, Axel?. I can see how the ProDrive could trigger the AR unit, but I don't see (from the user PSX-AR lit) how to accept this signal.

But assuming I've simply not read / understood completely, as you've pointed out, one must select either DC or DCC ProDrive mode. So when the second gap is hit, how does the AR unit "talk back" to the ProDrive? Only via DC, correct?

===Cliff


----------



## Axel Tillmann (Jan 10, 2008)

If ProDrive is hooked up directly to DCC then ProDrive has the ability to be triggered to throw the switch. Therefore there can be a trigger in the reversing loop that (i.e. reed switch) that give a short pulse to ProDrive which initiates throwing the switch (unless the switch is already in the position the trigger wants to move him to). There are two triggers (one ofr each switch position). COuld also be used to throw via push button the switch manually (some of our customers do that).


----------



## CliffyJ (Apr 29, 2009)

Posted By Axel Tillmann on 27 Aug 2011 02:17 PM 
If ProDrive is hooked up directly to DCC then ProDrive has the ability to be triggered to throw the switch.  Therefore there can be a trigger in the reversing loop that (i.e. reed switch) that give a short pulse to ProDrive which initiates throwing the switch (unless the switch is already in the position the trigger wants to move him to).  There are two triggers (one ofr each switch position).  COuld also be used to throw via push button the switch manually (some of our customers do that).


----------



## CliffyJ (Apr 29, 2009)

Posted By CliffyJ on 27 Aug 2011 02:21 PM 
Posted By Axel Tillmann on 27 Aug 2011 02:17 PM 
If ProDrive is hooked up directly to DCC then ProDrive has the ability to be triggered to throw the switch. Therefore there can be a trigger in the reversing loop that (i.e. reed switch) that give a short pulse to ProDrive which initiates throwing the switch (unless the switch is already in the position the trigger wants to move him to). There are two triggers (one ofr each switch position). COuld also be used to throw via push button the switch manually (some of our customers do that).



If I understand you correctly, that would mean using the reed switches to "manage" the turnout position, and the AR unit to "manage" non-shorting, in an independent manner. Does that sound correct?


----------



## krs (Feb 29, 2008)

Guys, 

The whole point of using an auto-reverser is to not have to use reed switches for control of a reversing loop. 
If you start down that road then your locos and anything else that is meant to trigger the reed switch will need a magnet mounted underneath. 

Knut


----------



## CliffyJ (Apr 29, 2009)

Sorry for the double-post. 

If that last "system" works, it sounds "idiot proof" as Axel said. But two complexities occur to me. First, whatever is triggering the reed switches must be present on every loco, and any car that might be used as the last one (for backing out). Second, this extra layer is in addition to the first, that is, the gaps, AR unit, metal wheels on the last car, etc. 

It seems to me that either the AR unit or the ProDrive needs to be in control of both loop polarity and turnout position. 

Just my opinion, I'm the learner here. 

===Cliff


----------



## CliffyJ (Apr 29, 2009)

Thanks Knut, we were writing at the same time, but I concur...


----------



## Axel Tillmann (Jan 10, 2008)

Knut:
 
AR and reed switches have nothing to do with each other.  The reed swtiches control the swtich in an automatic fashion, instead of the operator switching the switch, or instead of an automation program doing the job.  So the purpose of the reed switched do not defy the purpose of the AR.


----------



## CliffyJ (Apr 29, 2009)

Posted By Axel Tillmann on 27 Aug 2011 02:44 PM 
Knut:

AR and reed switches have nothing to do with each other. The reed swtiches control the swtich in an automatic fashion, instead of the operator switching the switch, or instead of an automation program doing the job. So the purpose of the reed switched do not defy the purpose of the AR.
I believe that is what I was trying to describe. They would be independent functions (turnout position and rail polarity).

Thanks Axel,

Cliff


----------



## krs (Feb 29, 2008)

Posted By Axel Tillmann on 27 Aug 2011 02:44 PM 
Knut:

AR and reed switches have nothing to do with each other. The reed swtiches control the swtich in an automatic fashion, instead of the operator switching the switch, or instead of an automation program doing the job. So the purpose of the reed switched do not defy the purpose of the AR.

Well yes, that is true in general.

But the whole idea of using this particular auto-reverser, the PSX-AR, was that it could also control the turnout (without any additional reed switches or magnets)

As I understood it from postings earlier in this thread - 

Cliff wanted to be able to throw the turnout under his control (either via DC, pushbuttons, or DCC) so he would control which way the train would transverse the reverse loop and the Auto-Reverser would then automatically line up the turnout correctly for the train to exit the reverse loop.


That, according to earlier posts, was no problem using the PSX-AR and the ProSwitch - is that no longer true?

Knut


----------



## CliffyJ (Apr 29, 2009)

Posted By krs on 27 Aug 2011 02:52 PM 
Cliff wanted to be able to throw the turnout under his control (either via DC, pushbuttons, or DCC) so he would control which way the train would transverse the reverse loop and the Auto-Reverser would then automatically line up the turnout correctly for the train to exit the reverse loop.


That, according to earlier posts, was no problem using the PSX-AR and the ProSwitch - is that no longer true?

Knut 

You're understanding things just fine Knut; all I want is a simple way for the turnout and polarity to line up, in an automatic fashion, with the ability to override (preferrably with DCC, pushbuttons if I have to, but not both). With the least equipment necessary.

Thanks,
===Cliff


----------



## CliffyJ (Apr 29, 2009)

OK, here's the summary in my mind. By the way, I've already purchased the PSX-AR's and ProDrives. 

1. Let the PSX-AR control the ProDrive, via DC mode 
2. Place the gaps far enough away from the turnout so that the ProDrive has enough time to throw it, once commanded by the PSX-AR. 
3. Ensure the isolated section in the loop is at least 1 (max) train length. 
4. Optionally trigger the PSX-AR (and thus ProLine) either by: 
4a. Pushbuttons 
4b. Stationary DCC decoder 

That seems to me the simplest approach. Anyone concur? Disagree? 

Thanks again to all, for this hugely informative conversation! 

Best regards, 
===Cliff


----------



## Greg Elmassian (Jan 3, 2008)

Good enough... start hooking things up! 

Greg 

(that means I concur!)


----------



## CliffyJ (Apr 29, 2009)

Thanks Greg!!


----------



## rdamurphy (Jan 3, 2008)

There is something that may be slightly simpler: 

The train enters the normal side of the turnout, crosses the gap, triggers the AR, then after clearing the turnout, the locomotive triggers the switch, moving it from normal to reverse. 

Now, of course, nothing returns the turnout from reverse to normal, so the next train through takes the reverse side of the turnout, triggers the AR, then after clearing the turnout, the locomotive triggers the switch moving it from reverse to normal. Then you only need the AR for the polarity, one red switch on one end of the loop and one on the other to line the switch in the correct trailing position for the approaching train. 

I hope that was clear. And not like mud, LOL! 

Robert


----------



## Greg Elmassian (Jan 3, 2008)

Simplest thing is spring switch, so no electricity to operate switch. AR handles polarity. No other wiring or work or electric switch motor. But he asked for the system to throw the switch, and also remote control of switch. 

My take on simplicity and reliability is the least wires and least components, no triggering track separate if possible. 

Greg


----------



## Axel Tillmann (Jan 10, 2008)

Posted By Greg Elmassian on 28 Aug 2011 10:18 PM 
Simplest thing is spring switch, so no electricity to operate switch. AR handles polarity. No other wiring or work or electric switch motor. But he asked for the system to throw the switch, and also remote control of switch. 

My take on simplicity and reliability is the least wires and least components, no triggering track separate if possible. 

Greg Not really, especially not with a powered frog









In addtion the condition of a spring loaded switch is as such that either the spring is too strong for lite cars or to weak to overcome the increasing friction of the accumilating dirt.  You will be constantly maintaining the points and the spring loaded mechanics.


----------



## krs (Feb 29, 2008)

Spring switches - something I thought existed only on model train layouts, not in real life. 

But I was wrong: 

http://www.youtube.com/watch?v=TQZv8w2wMXs 

Here are some technical details: 
http://www.voestalpine.com/vae/en/p...ystems/special_trackwork/trailable_point.html 

Powered frog on a spring switch - that can be taken care of by an electronic module made by Dietz - or just don't power the frog. 

Knut


----------



## Axel Tillmann (Jan 10, 2008)

Posted By krs on 03 Sep 2011 04:54 PM 
Spring switches - something I thought existed only on model train layouts, not in real life. 

But I was wrong: 

http://www.youtube.com/watch?v=TQZv8w2wMXs 

Here are some technical details: 
http://www.voestalpine.com/vae/en/p...ystems/special_trackwork/trailable_point.html 

Powered frog on a spring switch - that can be taken care of by an electronic module made by Dietz - or just don't power the frog. 

Knut 
Knut,

quite often poeple, however, overlook that the cars are not 1:22.5 (1:29) in weight, while the friction forces/spring force are at least in correlation or even worse.


----------



## CliffyJ (Apr 29, 2009)

Thanks guys. You're confirming my suspicion that the turnout needs to be thrown properly, for the train's exiting of the loop.


----------



## krs (Feb 29, 2008)

Posted By Axel Tillmann on 04 Sep 2011 03:39 PM 

Knut,

quite often poeple, however, overlook that the cars are not 1:22.5 (1:29) in weight, while the friction forces/spring force are at least in correlation or even worse.


Axel,

I was just surprised that this spring switch operation is actually used on the prototype - not that it's necessarily a good idea on the model although I have seen layouts where a spring switches are in operation successfully. What really intrigued me was the delay before the turnout returned to its original position - that's why I included the link to one company that manufacturs them.


Last time I was in Europe and took an excursion on a small tourist railway near Berlin, they had some of the passengers, including me, throw the manual switches.
Boy, that wasn't as easy as it looked - not only do you need a fair bit of strength but you have to have a flying start to throw the switch. The rail doesn't have a hinged part like on the model train switches, the rail actually has to bend.


With LGB switches, te only ones I'm familiar with, you get two types of operation when the switch is cut open depending on the drive that is used - no idea how other manufacturer's switches behave or if cutting open a switch without derailment is even in the cards.


You bring up another interesting subject - the optimum weight of the rolling stock.
For H0 there is a formula that was developed which allows one to calculate the optimum weight based on the length of the car.
In G-Scale that was never done as far as I know even though the hobby has been around for many, many years.
I recall a discussion on one of the forums quite a while back - the end result was actually an emperical formula that seemed to work well, but it was never picked up by any of the standards organizations.

Knut


----------



## Greg Elmassian (Jan 3, 2008)

There are very inexpensive "single wire" autoreversers that can be used to power a frog without any other wiring, DCC in, single wire out to the frog. Inexpensive... 

(Check out Tam Valley "Frog Juicers".. 

But that did add cost... 

Greg


----------



## Axel Tillmann (Jan 10, 2008)

Knut:

I have done experimentation with brand new switches on the bench. I bought a bunch of springs and tried to identify the minimum spring strength in order to ensure that the switch remained positively thrown, even if I dirtied up the switch (fine garden soil). It turned out that the engines always the switch open, but cars under about 1 1/2 pounds (translates to about .75 weight per axle) could not guarantee that the switch opened, and if you reduced the spring tension, you couldn't guarantee that the switch went back to its original position, even if the switch was still correctly moved by the manual or electric switch machine when there was a full left to right (or right to left) motion. The longer way seems to have been able to afford less spring power then the minimal distance that is caused when the flange is opening the points.

to be on the save side I would say 1 pound axle pressure is correct which translates to 2 pound weight (or in 1:1 24 pounds) which is actually not a lot considering the real weight of the prototype. But many in our hobby use the cars as is, and for example an LGB low sided gondola weights only 1/2 pound (if all that).


----------

