# OFF the beaten Path - Tunneling along



## SD90WLMT (Feb 16, 2010)

For a little diversity,...

This is a SD40T-2R, "Tunnel Motor", run by SP & DRGW 
The complete frame is a custom design, hand built unit. It has modified bolster brackets from SD70Mac, modified HTC side frames from SD40-2 locos, stretched A/C fuel tanks, sits easily on 8 foot radius curves, in-spite of truck mods, hand made frame, close clearances all working together. Uses my modified 70 motor blocks also. Super sound in progress - 3" Visaton in tank, 2" Visaton up top - thru a fan opening. All up weight about 18 pounds. The first of many of these...





















..... someone to sit inside!










..... sitting on a #10 turnout drawing, diverging track...










..... scale frame appearances, just tucked in above the side frames...










..... scale appearances of the draft gear pocket and details with coupler...










..... modified steps, new tread decking, details added...










My close train buddies have been after me to share my work,...

So here's to your winter projects and motivation... stay indoors and stay warm, keep building...!!!!!

No.2 Tunnel, to be a DRGW unit.. built on a stretched SD40-2 frame, stock trucks, etc.










A no.3 frame is in the works, as are more hand made parts for many more custom frames.

This is a shared build project with another train nut.

Dirk
DMSRy.


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## harvey (Dec 30, 2008)

Hello Dirk,
A nice little project you have going here, but we (I) need more info please. Is the frame reinforced on the underside or are you relying on the body attachments to keep it from sagging? eighteen pounds is a lot to carry around without reinforcement. Track power or battery? the latter would be at least two pounds I would think. Can you give us a bit more info on the tread plate for the decking, I would certainly like to know what you have used.
I currently have a few projects on the go, but I don't think I'm at the stage of exposing all my screw-ups to the rest of the world, not just yet anyway.
I'm really looking forward to seeing your progress and thanks for letting us see what you're doing with these engines so far.
Cheers.


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## SD90WLMT (Feb 16, 2010)

Harvey,

Greetings to you up North! Let me try to answer a couple of your concerns now. I'll need to process or take more pix for full clarity here...why we have threads...keep going into them..
To me the average new large loco fresh out of a box weighs about 10 pounds. I use to run 6 batteries in my SD70, which ran about 1.5 pds each. ( the 70 weighed 19.375 #'s ).
I'm swapping to 4 - 6 volt batteries...these are right @ 2.0 #'s each. Add a decoder/receiver set, both a 3" & 2" speaker, switches..fuses..a few more odds of plastic not normally in a loco. Now we're pushing 19 #'s of beast.
I build my custom frames using a unique overlapping puzzle concept. This creates stronger joints between glued parts...
I'll show by pic how some of this works soon.
Also..I do not use the hood screws you are referring to. I have adopted a slip-on hood policy starting with my first large scale loco..hiding just inside the hood, are 2 mock-hood sides, tied to the frame itself with a number of bulkheads to add strength and define spaces within for lead acid batteries to fit.. This added structure acts like a bridge, more than stiffening the frame without the hood in place at all and spreading the increased load over the trucks.
This makes it very easy to build and gain access to all the components inside a typical loco, without the need of turning one over or potential damage from same.
As you can guess here..I'm a battery runner!

As for the diamond tread plate..it is sold at Tower Hobbies. It is actually an HO product in scale tread design and spacing. By Plastruct I believe. This sheet runs .022" - .025" in combined thickness..so used as an overlay..adds very little thickness on a G sized loco. I simply file and sand off the tread pattern surface before over laying this on existing locos.

I encourage you to "fix your screw ups", and get posting buddy...there are not enough of us building locos these days! Your work is always impressive to me..and I like the variety you add to the hobby..

Good Luck...keep building!
ThanX
...Dirk


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## Scott (Jan 29, 2008)

Mate, she's a beauty - would like to see all finished loco's lashed up and running a consist. It'd look so sweeeeeeeeeeeet!


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## harvey (Dec 30, 2008)

Thank you Dirk,
Good information for us all. The inner shell is a very good idea (can't believe I never thought of it) This afternoon I have just rough finished the outer shells of a couple of engines I'm working on and I've used an underfloor attachment with screws using the outer shell as the stiffener. I plan to use a brass stiffener strip along the inner edge of the base plates to compensate for the battery weight. I'm also a battery runner.
I'll have a look at some progress photo's and see if they're worthy of exposure to the outside world.
Thanks as always.
Cheers.


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## SD90WLMT (Feb 16, 2010)

My original early goal was naively basic.... First loco bash...on batts...all I could think was..."how many batteries can I shoe horn inside a loco ?" eventually stumbling on this thought....IF....I can cut a hole in the frame...set batteries in the tank...it would be very full..obviously cutting a hole as long as the fuel tank was gonna seriously compromise the frame strength and integrity. But...I followed thru....I reasoned I just needed to build a bridge spanning the frame length...I'd have done this on many steel designs...why should it be harder on a small toy...

Hence the concept for the faux inner hood was born....the first step was the tuffest. It has literally been down hill from there...I have built ever loco project I get my hands on this way..the basics always work out. And..2 locos have been run..
My SD70Mac - RED lead loco for Longest Train event on the last weekend.
Also a stretched SD60T-2R build...with 6 batts also has performed well...

The inner surfaces of each hood are completely devoid of any screw tube extenders or other protrusions that will rub or interfer with the inner hood sides. I have settled building sides from .060" black sheet...I use a number of bracing or reinforcing building ideas to strengthen all joints involved....

I'll dig up more pics of this part of the frame work....

Dirk


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## SD90WLMT (Feb 16, 2010)

Scott...ThanX...for you and everyone else..we will do an all Tunnel lash-up...!!!!


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## Garratt (Sep 15, 2012)

He even has legs! 










Andrew


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## SD90WLMT (Feb 16, 2010)

... And properly placed arms & hands on correctly postioned controls..thanks to help from our buddy Craig!! a little weathering and the control stand is much better suited to a cab..what may not be apparent is the re-angled stand...rotated around towards the engineer..properly positioned also...pix are a big help for this stuff..

Morning mates'.... Coco time...


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## SD90WLMT (Feb 16, 2010)

Harvey, 

I'm diving deeper into the basic frame build here. While it shows more, the all white plastic makes it hard to tell yet. I'll try to explain where I can....

There are 3 plies in play here;
The main middle layer is full width, x .060" thick
The upper strips run the length of the loco, setting the inner faux hood side location, x .060" thick
The lower strips run full length, x .040" thick, setting the lower frame I-beam position 



















Rear truck opening










Front truck bolster pivot pocket










Front truck in place, fuel tank installed, note clearances for rear wiring to power motor 










Rear truck clearances










End plate support bracing for draft gear and coupler mount 










This covers the lower side of the frame build.


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## SD90WLMT (Feb 16, 2010)

Now on the upper side of the frame, we can get to the faux hood side walls.

These just go inside full height at the cab rear wall.










The basic pair of side walls in place










While the bottom again, this shows the rear bulkhead of the faux hood.










Top view of the inner parts on the pad mount for the coupler










The stretched fuel tank










The rear frame and step changes from a SD40-2 loco compared to a SD40T-2R










At the rear hood lower is the side cooling air intakes, specific to Tunnel motors. I've located a shelf here, added cooling holes to draw air flow thru from the scale openings to flow over the QSI Titan 10A Decoder installed on edge with cooling fans located above the decoder to draw warm air flow off the decoder, up and out thru the top grilled openings, literally matching the cooling system flow on the real locos










Parting shot on its feet, with a cabeese










more to follow... tunnel on guys


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## SD90WLMT (Feb 16, 2010)

I am building locos using My own frame design. I'm also building locos using a modified approach based on USAT 40-2 frame. First it needs to be about .75" longer to meet a Tunnel length. I remove all the molded on details and start over, adding back my own details in a more refined manner. Better frame appearances that close the gap to the trucks a lot more than out of the box. The truck frames are used almost as stock units. I remove the small screws, replacing them with flat heads to provide increased clearances to allow the I-beam frame to be built inboard as much as practical.










A more substantial frame can now be built to improve the appearance of the loco










This shows the frame rear portion, before the plates are added










this view gives a pretty good idea of the before and after of the I-beam frames and the relocation inwards some










This is the build up on top of the USAT frame, very much the same as My custom frame is










...Also notice in the background above - Tunnel frame No. 1, on it's custom frame...
.... more to come, course My "Skunk Works" is inactive due to some issue called climate warming currently in effect in a neighborhood near all of us!

Thanks again, 
Dirk
DMSRy.


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## Michael Glavin (Jan 2, 2009)

Dirk,

Another great thread!!!

How are the faux walls attached to the frame? Is there an additional piece of styrene running lengthwise with the frame that the wall is anchored to?

Michael


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## SD90WLMT (Feb 16, 2010)

I'll have to work up some close up pix me thins for this area for you gents!

Thin a multi-lam corner, but I use some angle stock to reinforce corners also.


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## SD90WLMT (Feb 16, 2010)

Trying to get closer to faux wall attachment with pix I have currently on hand.

The rear bolster pocket adds glue surface area to the rear of the walls










The front pocket under the cab










... an additional view of the decoder shelf prior to installation










... more on the coupler pocket mount, plus cap screw, with tubing sleeve pivot 










... the small crescent slot to remove the sleeve with small needle nose pliers, to allow pulling the coupler out










the coupler shank is filled internally, this creates a single pivot point, with out compression such as works on a freight car, matching a loco arc or swing. there are plates top and bottom to carry the loads, .... the shank also cut a bit shorter for clearance to the power truck front face


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## SD90WLMT (Feb 16, 2010)

Here is My planned internal placement of components for a Tunnel motor loco..

Without experience one would not know that packaging all these items in a Tunnel loco is more space challenging than a normal SD40-2 loco can be.... the goal of leaving the low side air screens visibly open and clear, in the "see - thru" fashion of a tunnel, is not easy to do!










This gives a side by side look at the internal layout with the frame along the top side to compare 










Well, good additions for now, off on break... Thanks again


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## jimtyp (Jan 2, 2008)

WOW! Really nice Dirk. Would have been on the verge of criminal not to share ;-) Thanks for all the detail pics, and that is definitely detailed. 

-Jim


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## SD90WLMT (Feb 16, 2010)

It might have forced you to travel to place cuffs on a fellow modeler Jim...LOL...

..glad you like the loco...!! Thanks

D


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## harvey (Dec 30, 2008)

Hi Dirk,
Thanks for going the extra mile here and posting so many (informative) photographs. I see with all the batteries you're going to install why the weight is so high. I'm planning to use the CR1605 batteries, but only one per engine! I did do as you have done and cut out the sole plate to accommodate the battery and provide the hood clearance. This opening has been covered on the underside and the main frame reinforced. I have used 1/8" styrene for the sole plate and hoods. I have also done as you have and provided extra ventilation for the decoder and sound system. I actually do this on all my engine conversions, keeps things cooler in this confined space.
I see you've modified the trucks which tells me you've been working on this project for quite a while. My little project requires A -1- A trucks and these are still in the "will it or won't it stage" Lots to go on these yet.
The concept of using a sleeve arrangement for the hoods is a great idea and as you noted, allows all the internals to be placed prior to installing the hood. Next time I will certainly need to look at this options.
Thanks again for all the fabulous detailed photo's.
Cheers.


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## SD90WLMT (Feb 16, 2010)

Harvey,

I briefly searched your CR batteries...I found 14.8v units in various amp hrs....?
To add to this, I started with 18 volt packs in My 70 loco... I'm now switching to 24volt sets per loco. Add to the changes, the Power Sonic 6V. I used earlier was a 4.5AH batt. 
Recently they designed a fresh batt. Still built on the same case size, but now in a 5.5AH format. These fit in My faux loco hood confines just the same. They also weight the extra 1/2 pound each from the higher density. The result is a nice upgrade...without redesign on My part...also an increase in watt hours is a nice addition.
Many have tried to convert me to Lipos and other new technologies. I have nearly jumped off a few times in this direction....still...not there...far more costly..across the board. I considered again with these new tunnel builds...then I found the weight loss from doing so. Off to shops in search of lead I went....! Then reality hit hard...lead is no longer inexpensive.. calculations revealed to make up for weight loss to new Lipo batteries, could run hundreds of $$ to regain the weight in lead....plus the space to place it...
I stayed on the path I've wandered for years...moving over to the 5.5 AH units soon....power + weight in one package for 50 bucks...sold me!

Time wise these where first started last Fall, in 2014. I had a knee up on them. The chassis designs for previously building huge SD9043 locos gave me insight to a fresh design for a tunnel frame...just straight forward building..no splice n stretch strategy. I was all ready on a path following rework of the HTC frames to fit 70 motor blocks with the more compact metal brackets...for many loco projects ahead of me. I'll need to dig out pix of that work next. Building fuax hoods was a no brainer on My bench...so there was a lot in play to begin with. Then the project took a twist when Michael G. showed interest in building tunnels right along side my work...we paired together hoping to draw from each others strengths and abilities to get what we both wanted. This will take years..but we are after an armfull of power for us...Tunnels are one of my most favorite locos...add SD90's to the list and I'm a pretty happy train guy!!

Thanks Harvey...stay warm buddy...

SD - "Super Dirk", as I'm frequently being refered to behind the scenes...and believe me...there are scenes behind the curtain!!! LOL...my buddies keep me going...!!


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## SD90WLMT (Feb 16, 2010)

As one can tell from following the presentations here, I use full sized drawings of locos - in exact 1/29th scale to build and use as reference.

The basic key number here for those even remotely inclined to dive in is the overall frame length to build to.
A number of locos use this same frame design with the rear step ladder, not steps.
SD40T-2, SD45T-2, SDP45 are the 3 locos built on the same base frame length.

Here is your ticket number...

Over the end plates, front to rear, build to the model length of 27.517"...

... if your get this right, every thing else will fall in place.

Try one. Paul Burch has a nice SP unit built many years ago!

In today's present modern climate of power sales to smaller roads all over the country and beyond, there are many colors to choose from, & ideas to model RR's in now.

Have Fun.

DMSRy.


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## SD90WLMT (Feb 16, 2010)

Now for power truck lessons:

There are different truck frame designs under locos....

SD45 - Flex-coil trucks ... from Aristo Craft
SD40-2 - HTC trucks ...... from USAT

yet .. all tunnels, be it a 40 or 45 series only use the HTC truck design...

So this has some bearing on the best frame choices to build either loco from to begin with...

Then loco choice also changes the cab position on the frame, as the 45 cab is placed further forward..making it easier to stick with the 45 frame, but rebuilding the bolster areas...

yet on a SDP45, the early flex-coil truck is used only, yet on a tunnel frame...

Corn-fused here yet??? ha..there is a lot of basic stuff to swallow before jumping in head first...

It is easy nuff to figure, but one choice affects another, with needed changes as the result.. changing trucks installs from one breed to the other can complicate the process....

Take yer time, decide what loco interests you have, and how much work you want to do, or are able to tackle for any one of these off breed locos..

Dirk, course - help is always out there...join one of our "Train Therapy Groups", for those addicted to trains and such... its all good!


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## SD90WLMT (Feb 16, 2010)

Some really nice "Inspiration" here....

a very full scale - REAL - coupler here!!










...and my feeble attempts to replicate same in 1/29th.










getting this close drives me nuts sometimes... but is so much nicer I force myself to have FUN!!!

Dirk


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## Paul Burch (Jan 2, 2008)

As Dirk mentioned, I did a S.P. SD40T-2 back in 2003. It is modeled pretty much in the as built version. Dirks will have a little higher level of detail and I'm guessing some updated features like ditchlights. Anyway here are a few photos that will show where Dirk is headed.


















































This last photo shows the SD40T-2 coupled to a SD40R,1990's version.


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## SD90WLMT (Feb 16, 2010)

Morning Paul.

Thank you so much for sharing your fine Tunnel motor with us...I always enjoy your work... (still waiting on a recent paint you did on a pass car tho!! ha)
I'll work on my loco builds as I have time..yet no painting in the for seen near future until I build a new work shop this next year. Then my wishes are to be more productive..and catch up on many painted needs for my G stuff... in a huge nearly 80% complete G spray booth. 

I'll likely model this first snoot as a late model SP unit.....Rio Grande version..speed lettering..revised ligthing..Ditch lites..etc.

Thanks again Paul
Dirk


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## Paul Burch (Jan 2, 2008)

Dirk,
I was a little hesitant about posting the photos because I don't like to step into other peoples post strings like that. I will get some photos of the private passenger car up at some point. Maybe when its warmer outside. My efforts now are on a S.P. GS1 northern.


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## SD90WLMT (Feb 16, 2010)

Paul,

I don't mind a bit...how we help each other...

Thank You!


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## Paul Burch (Jan 2, 2008)

Dirk,
Now that this comes up it reminds me I still need to send those 2 axle heavyweight trucks back to you.


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## SD90WLMT (Feb 16, 2010)

This topic has developed well. Many of you have shown a lot of interest...tackling a project of this extent is nearly overwhelming in itself..... It has evolved from other earlier projects as well, in a normal traditional learning curve. - one thing leads to another...We all watch in amazement at Burl's incredible projects..others have done feats of wonder over the years..

What I'm leading to here...is simply sharing this project is the result of many people bringing some form of help..assistance or ideas to further this series of Tunnel motor locos you are seeing presented...

Both myself & Michael have spent months sharing our interests in having models like this..which lead to us both going...gee..what if we do this together...??? A simple beginning for 2 modelers after a loco otherwise not found on a store shelf...we didn't have all the answers...we still don't...we'll figure stuff out on the way or get help. I just posted a real pic of the rear end plate and coupler...this is from a photo essay another friend did...Brandon was off on a road trip with friends. They stopped at a museum...took mind you about 150 pictures of one of the last SP SD40T-2's still in grey paint...stored in one piece...having these close up pix are a great help to solving questions that come up in a project of this nature. I and Paul have visited over his work a few times...His loco is here to see...been run on his nice layout. Craig adds a wealth of practical knowledge he has experienced being a operator of locos years ago.... Yes..Burl has helped me finally obtain my illusive door latches..these have held me back for years...now they are produceable..

All of this combined energy and effort is flowing into the models being built here. It is not something I could just do on my own...

Our overall goal is upwards of more than a few of these in a 40T version...moving on to a hand full in the 45T camp also. Then like maybe 2 in the SDP45 passenger turned freight versions..

What is happening here is more a proof of concept approach to the many aspects of parts and ideas to build all we would like to have... Then build each part from the best methods or approach for that part....with the final building to follow this...

I can't Thank everyone enough for all the help in reaching towards this goal!!!
Pushing 1/29 locos along...in our hobby!!! Thank You...
Dirk & Michael


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## Brandon (Jul 6, 2011)

Looking good Dirk!!


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## Scott (Jan 29, 2008)

Keep up the good work.


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