# Train speed



## Dan Pantages (Jan 2, 2008)

Hi all. Several years ago at the Summer Steam-up there was an arch type structure that sat over the track and recorded the scale speed of any train that went through/under it. It could be adjusted for scale. Does anyone remember it and do you know who built it and if I could buy one? I'm sure I didn't dream it up but all the people I know in the hobby do not remember it.


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## David Leech (Dec 9, 2008)

Yes Remember it.
2007, and here is proof, with you checking it against your Hot Wheels one.
No idea who made it, but I'm sure you can find someone with electronics knowledge to make you one.
Cheers,
David Leech, Delta, Canada


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## Greg Elmassian (Jan 3, 2008)

I have one with an arch, built by Dave Bodnar

trainelectronics.com

I have the arch and a wireless car


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## Jeff Williams (Jan 8, 2008)

Dan,
I think that Bob Trabucco built the speed arch. His email address is in the National Summer Steamup Attendee Roster.


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## Dan Pantages (Jan 2, 2008)

I have made contact with Dave Bodnar.


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## Pete Thornton (Jan 2, 2008)

Dan,
I have always thought there is a different approach to "scale speed". If a real loco is running at 30 mph, then it's wheels are turning 'x' times a minute. (Shouldn't be difficult to figure out if you know the wheel size.) You can apply the same logic to a model to calculate its speed just be observing how many revolutions the wheels make in a minute. If they revolve at the same rate as the prototype did at 30mph, then your model is going 30-scale-mph.


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## David Leech (Dec 9, 2008)

Pete,
That might be possible on a nice slow moving K27 or similar, but when a 1/32 express loco at a scale 90 mph passes, it is possibly impossible to count how fast the wheels are revolving!
Plus then you have to measure the wheels of any loco that comes to run!
Good idea in theory, but hard to actually make work.
Cheers,
David Leech, Delta, Canada


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## Greg Elmassian (Jan 3, 2008)

Yes, true you can count rpm, but hard to do on a steamer, impossible on a diesel (but not sure Pete knows what a diesel is ha ha!)

I have the hoop for G scale, and Z scale, and also a car that transmits back to the base station it's speed and voltage:





Speedometer Car


Greg Elmassian web site on large scale trains and garden railroads, cigars, and computers




elmassian.com





(all in good fun Pete)

Greg


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## Pete Thornton (Jan 2, 2008)

Greg Elmassian said:


> but not sure Pete knows what a diesel is ha ha!)


I have at least 3 diesel locomotives. They just don't look like yours.


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## Greg Elmassian (Jan 3, 2008)

I just had to poke you a bit, from what I've seen, you have a wide range of stuff... love those little boxcabs...

Greg


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## ferroequinologist (May 8, 2016)

For 1:20 to 1:22 scale trains I wrote this approximate miles per hour scale speed down from somewhere but I forgot where. It's easy to do when running. You time how many seconds the loco takes to travel 5 feet. I'm not sure where I got this from but a quick check of the train against a marked 5 feet and the second hand on my watch gets me in the ballpark so speak.
For a loco travelling over a five foot distance if it takes 2 seconds it's travelling at 38 to 40 mph, 3 seconds its travelling at 25-27 mph, 4 seconds and it's 19-21 mph and 5 seconds 15-17 mph. All approximate and I am not sure if its even accurate but the trains do look like the speed indicated. Saves building a special bit of equipment to measure speed, any way it's whatever you want to run the train at anyway but a slow speed makes our small layouts seem bigger?
Russell


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## Greg Elmassian (Jan 3, 2008)

So Dan (the OP), are you considering having Dave make you one? I was very happy with Dave and the result.

Greg


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## Nick Jr (Jan 2, 2008)

I was at a persons layout, he had a device built into a box car that transmitted the speed to his I phone, that's all I know about that one. Also saw on a forum or magazine someone built one made from a bicycle speedometer. Tried looking for it a few years later and came up empty.


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## phils2um (Jan 11, 2020)

I don't claim to have originated the idea (I stole it from someone else's post somewhere) but here's my bike speedometer implementation.










A couple of looks at the speedo's reed switch and the spoke magnet:










The magnet is just taped to the wheel axle with black vinyl electrical tape. The speedometer's display and reed switch are attached using low temp hot melt glue. A closer look:










Calibration for mine couldn't be simpler. The calibration factor is based on a bicycle wheel's circumference measured in centimeters. For this LGB wagon the cal factor = 3.1 x Pi x 22.5 = 219. (3.1 is the LGB wheel tread diameter in cm and 22.5 is my rr scale, 1:22.5.) The speedometer internally converts the reed pulse rate to kph or mph depending on the calibration factor and selected speed display. This was an old bike speedo I had. It was inexpensive at the time. I think I got it on sale for around $15 - $20. Similar wired speedos can still be had for about the same price today.


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## Nick Jr (Jan 2, 2008)

Phil, that is what I saw, just couldn't find it on web searches, thank you. I'll save it this time.


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## Dan Pantages (Jan 2, 2008)

Greg, I am in contact with Dave. He is not sure he has any parts left but he said he would look. I've seen the bicycle speedometer type and I made up a spread sheet for several different scales that gives you the speed when you time a train over an 18ft (three 6ft sections of flex track) distance. What I would like is a portable unit that does not need to have a special car in the consist. Though I run mostly 1/32 scale I do have some 1/20.3 scale and 7/8 scale so I would like to be able to change the scale speed read out, which I understand Dave's unit can do.


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## Greg Elmassian (Jan 3, 2008)

Yes, Dave's unit is multi-scale which is really nice... the hoop can accommodate all kinds of scales. Also, the accuracy is pretty high, which I needed because I use it to set up custom speed tables in my DCC decoders, i.e. with 128 speed steps, my locos are pre-calibrated to equate the displayed speed step with actual scale miles per hour.

So, I can consist any 2 locos together and they match, and also just glancing at the throttle tells me the exact scale speed. It really helps when you have "junior" engineers that want to run at 200 miles per hour! (I also set the speed table to "flatten out" at prototype scale speed, so it's impossible to run over prototype scale speed.

Once done (done once in the loco's lifetime), everything just works smoothly together.

Greg


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## zephyra (Jan 2, 2008)

Greg Elmassian said:


> Yes, Dave's unit is multi-scale which is really nice... the hoop can accommodate all kinds of scales. Also, the accuracy is pretty high, which I needed because I use it to set up custom speed tables in my DCC decoders, i.e. with 128 speed steps, my locos are pre-calibrated to equate the displayed speed step with actual scale miles per hour.
> 
> Greg


Running 1:32 live steam with no RC, I can only dream of having 128 speed steps - some of my locomotives are best described as either on or off

I've adopted a much simpler approach based on how fast I need to walk to keep up.....

Shuffle along <30 mph
Leisurely walk = 60 MPH
Brisk walk = 90 MPH
Running = too fast!

Robert


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## Dan Pantages (Jan 2, 2008)

I only run steam and it looks much better running at a scale speed.


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## Nick Jr (Jan 2, 2008)

Yes, steam is better at scale speed, can watch all the rod motion instead of just a blur.


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## Greg Elmassian (Jan 3, 2008)

Yes, ditto...


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## Nick Jr (Jan 2, 2008)

Check out the Climax thread. Lowest throttle I could get, and can actually see it struggle with a heavy load through a turnout.


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## Greg Elmassian (Jan 3, 2008)

Dan Pantages said:


> Greg, I am in contact with Dave. He is not sure he has any parts left but he said he would look. I've seen the bicycle speedometer type and I made up a spread sheet for several different scales that gives you the speed when you time a train over an 18ft (three 6ft sections of flex track) distance. What I would like is a portable unit that does not need to have a special car in the consist. Though I run mostly 1/32 scale I do have some 1/20.3 scale and 7/8 scale so I would like to be able to change the scale speed read out, which I understand Dave's unit can do.


The one I have from Dave has 1:20.3, 1:29, 1:32...


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## Dan Pantages (Jan 2, 2008)

Yes the same as what I have. I'm just building a "mount" for it that doesn't look to obvious.


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## Mike Toney (Feb 25, 2009)

Some of the problem is dealing with physics that you cannot scale down. The expansive power of steam is huge, but our models lack the mass tonnage of the real locomotives. Which helps temper that expansive power at slow speeds. We crack open the throttle and its off to the races, real ones just start easing into motion(having cylinder cocks open helps as well do remove any condisation in a full size locomotive). The SSP Slomo inertia device comes the closest to making a model behave like a real locomotive. I have been on and fired both Cass Scenic Shay 2(many many years ago) and NKP 587 back when it was running. The Slomo gives the model the inertia of simulated weight by using a gear reduction unit with a flywheel. I am all for realistic running speeds. Nothing spoils the look of so many of these beautiful gauge 1 and G scale locomotives that watching them run at warp speed and looking like a runaway train. The engine drivers that learn their engines and keep speeds in check, have my deepest respect and admiration.


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## TonyW (Jul 5, 2009)

Mike Toney said:


> The SSP Slomo inertia device comes the closest to making a model behave like a real locomotive.


No, it does not. A cheaper alternative is to just turn the gas down and run the loco at half its designed pressure. That works just as well.


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## Nick Jr (Jan 2, 2008)

Here's one at 25lbs boiler pressure, with about 1/8 throttle.


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## Greg Elmassian (Jan 3, 2008)

Have to agree with Mike, while weight scales nicely, the frictional losses, and power and control does not. The gearing down and adding rotational mass to increase apparent momentum sure looks effective from all the videos I have seen.

I think turning the pressure down works on very high quality mechanisms, but try to make a ruby run slow!

Greg


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## Nick Jr (Jan 2, 2008)

Rod locomotives are a bit more difficult but still doable. While adjusting speed the boiler pressure rose to 60. Still able to creep with only throttle control and no load. Don't own a Ruby, but have seen them creep at gatherings. None of my loco's have the fine throttle control modification.


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## Mike Toney (Feb 25, 2009)

One also cannot just turn down the fire on most Alcohol fired engines, so just turning down the fire rate is not a cure all. One can mess with the wicks but there is a limited to what one can do there as well. The problem is usually worse with light engine or little to no load to pull. Putting a decent load on the draw bar is the only way to slow down some engines, such as my Bowman 234 4-4-0 in O gauge. Even with 2 of the 6 wicks capped off, its a race horse with lots of power if you try to run it by itself. Needs several heavy tinplate coaches to tame its power(there is NO throttle on these pre WWII tinplate live steamers). You only methods of speed control is capping wick tubes prior to the run or just keep adding coaches or wagons till the speed is under control.


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## Nick Jr (Jan 2, 2008)

Mike, I agree, slower running locos do have a special charm. Alcohol and coal fired loco's do produce more heat, thus more steam vs gas. As can be seen in the video the boiler had 60lbs pressure, and release valve had started to activate. I don't have an alcohol or coal fired loco so don't know if they designed to run on more pressure, can someone help with that? If so speed control may be more difficult, and I never considered those with no throttle control. So I guess 'gas' fired loco's do have one advantage, easier to run closer to scale speed.


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## David Leech (Dec 9, 2008)

Nick,
As far as alcohol locos, as you know, they will run at whatever pressure the safety valve is set at.
Of course if you have it set low, and the fire can produce enough heat for a higher pressure, you will be blowing off continuously.
As far as speed control, it all depends on the loco, and the load it is pulling.
Here is my 9F, with small wheels and a nice heavy train showing that alcohol fuelled locos can run nice and slow at a scale speed.
Cheers,
David Leech, Delta, Canada


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## Nick Jr (Jan 2, 2008)

David, a great track set up, that loco is beautiful. And it can be run at scale speed with a load. Are those voluminous plumes due to the alcohol fuel or the weather at your location on that day? 
EDIT: further research shows water vapor is a by product fo burning alcohol, a benefit of that type of loco.


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## Belpaire (Feb 15, 2008)

Nick,
Water is a product of combustion of both alcohol and butane or anything that contains hydrogen.


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## David Leech (Dec 9, 2008)

Nick Jr said:


> David, a great track set up, that loco is beautiful. And it can be run at scale speed with a load. Are those voluminous plumes due to the alcohol fuel or the weather at your location on that day?
> EDIT: further research shows water vapor is a by product fo burning alcohol, a benefit of that type of loco.


Nick,
I am very fortunate to have had a garden that I can fit the railway in.
It was a cold January day, hence the nice plumes of exhaust.
Just above freezing, but in 'normal' summer weather you don't see any of it.
Too bad.
Cheers,
David Leech, Delta, Canada


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## Nick Jr (Jan 2, 2008)

David, since I use a Butane/Propane mixture I should get out there more in the colder months. The beautiful plumes are sure worth the look. Thank you


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## du-bousquetaire (Feb 14, 2011)

If you look at films of real locomotives in action, you usualy can see the rods turning over at a leisurly pace, if rods start to blurr you are running too fast. In the real world rods crosheads and pistons are so heavy that they will generate hammer blow. On tests of locomotives with throtles wide open lounched onto greassed track acheived running at incredible rotational speed and actually had their drivers lift of the rails; although they were charged with up to 35 tons per axle! This is what limits the speed at which an engine may run in the real world. Too often I see folks running a freight engine at 90 to 100 Mp/h speeds, which is awfull.Running trains at a realistic pace can be done though, it is usually like on the prototypes a question of adapting the train weight to the loco.
By the way the 9 F were with the Nord 150 B and P class notorious for being the fastest 2-10 -0 in history i beleive. You did get that wonderful smoke effect Davidand a beautiful run.


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## Pete Thornton (Jan 2, 2008)

AmyTopeteoOww said:


> David, you have a beautiful track.


Spam?


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## Mike Toney (Feb 25, 2009)

One has to have the depth of wallet after buying such an engine as the 9F, but then if you can afford that beautiful model, you probably have the income to spend a couple more thousand on a nice long rake of wagons to give it a load. My new RH Billy does well with several LGB passenger and freight wagons on the back with just RC control. Now I am using a RCS palm size tx with the knob to control the speed servo. I find that easier to get fine adjustments over a stick or pistol grip style radio. My coal fired Elke will get the slomo in it as it will remain manual control for now. Eventually the Billy will get one as well as it helps stablize speeds so when I go thru a dip in my roadbed, I dont get a unrealisic instant speed up, the slomo stablizes this and allows the engine to more smoothly traverse these areas more like the real one that has tons of weight to temper its own power. The models that I have seen with the device, do run much more realistic with less "babysitting" of the throttle. Can it be done just with the RC throttle, yes, but unless ones railway is dead level, it can get tiring after a bit.


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## David Leech (Dec 9, 2008)

Mike Toney said:


> One has to have the depth of wallet after buying such an engine as the 9F, but then if you can afford that beautiful model, you probably have the income to spend a couple more thousand on a nice long rake of wagons to give it a load.


Mike,
Just to clarify.
The 9F kit was $4500 delivered from California to Portland, where I picked it up to bring home.
The Roundhouse Billy with rc I see is $2500, plus I assume shipping and any duty payable, not sure how that works importing into the US.
So, yes, the 9F was more, but less than double, but then it is a lot more complex locomotive.
As far as the goods wagons are concerned, I bought them all in the 70's when I first started in Gauge 1, on my trips to the UK, and in those days most of them cost me £5 or £10 each.
They are all wooden, built from kits, most from before I was born.
I am retired on a pension and definitely do not have a deep wallet, but this is my only hobby, and I feel fortunate that I have been able to save and treat myself with this loco.
All the best,
David Leech, Delta, Canada


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## du-bousquetaire (Feb 14, 2011)

As David shows the secret to running meth fired engines at a realistic pace is adapting the load to the power output of the engine, which after all is exactly what the prototype railways did in the days of steam. You will observe that in that era there were a variety of classes of engines in service ranging for instance on the PRR from 440 (D16) to massive T1 and from light consolidations (by the mid '30 I guess the mogules had been phased out) to the Q2 or J1s. That was to adapt the engine to the load wherever it was possible, in modern railroading the MP people do it by adding or deleating units MUed with the lead engine. It is very important to adapt the trains weight to you engine. My friend Chris Ludlow also has mastered quite well starting a train (once the cylinders have been warmed up a bit) with a tiny regulator opening to get very progressive increase in speed, opening up as the speed increases. This makes for even more realistic running. I was a set designer, a great job, but with usually quite lousy pay (you have a fascinating job so you don't get much money, he he!) So I built up my stud of rolling stock over a long period of time, my first HP loco was a PLM pacific and for about 16 years all I had in rolling stock was about seven cars freight and passenger. Later as my revenues increased I was able to aquire a bit more, especially when I sold off all my HO equipment. If you are patient opportunities to get equipment and rolling stock at affordable prices come up now and then.
The only advantage to Gas firing which I have been able to see thus far is this ability to adapt the firing rate with the gas control valve, which does make slow running possible and easier. of course I am of the meth brigade.
Cheers, Simon


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## tacfoley (Jan 3, 2008)

Although I have a few rod locos and diesels too, I have no problem with my geared locos and figuring out how fast they are moving. If they are moving, that's good enough for me.


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