the MRH Forum

Cab, weight/frame for a potential TP56 kitbash project. Locos and rolling stock
Reply
Active Member 73 posts The Glorious Tachikoma Active Member 73 posts
The Glorious Tachikoma

https://imgur.com/a/f56Qz

 

I have been out of model railroading for a long time [ten years], but playing with SCARM and some track plan books has kind of given me the itch again, that and visiting the local rr club's open house night.

And I find that the TP56 exists and it really tickles my love for esoteric motive power. That and it seems a literal halfway point between a road switcher and a shunter/shifter, supposedly weighing 80-100 tons.

Having an old Athearn SD40-2 "B-unit" that realistically is better off scrapped, I have donor trucks, and I imagine a small motor from NWSL sized to fit within a heavily cut-down and cropped SW1500 shell will power it nicely. The SW1500 can even donate its rear cab face with some modification to the plinth the rear cab steps are built into. Cab sides are fine, but the front has very tall windows, and I'm stumped as to what could be used or harvested to complete those front windows. 

Big issue for me is going to be weight. I'm not seeing the practicality in re-using the SD40 frame as it leaves almost no room to mount a motor. Granted its not going to be asked to shift long cuts of cars, but for something whose prototype is advertised as having half the weight of its real-life donor and ostensibly 2/3 the tractive effort, some weight would be ideal.

Thanks to anyone who has any ideas. I might not want to build a layout yet but if I can get the materials together I'm going to try this one out. 
Reply 0
Chris Palermo patentwriter Frequent poster 979 posts
Chris Palermo patentwriter

3D print them

Another modeler has created the TP56 in N scale at Shapeways. You could contact the seller and see if he is willing to scale his 3D model up to HO scale and print the cap for you. He appears to have thickened up the window divider struts to accommodate N scale, but you could file these down to closer to scale thickness.

https://www.shapeways.com/product/4WF4SUJE2/tpc-tp56-locomotive-shell-n?optionId=63271804

As for weight, my only thought is to fabricate at least the frame in brass. It's mostly formed of straight shapes. Then fill any available space in the shell with lead shot saturated in white glue.

 
At Large North America Director, 2024-2027 - National Model Railroad Association, Inc.
Reply 0
Prof_Klyzlr Moderator 7,956 posts
Prof_Klyzlr

Frame

Dear ??? (The Glorious)

Quote:

 I'm not seeing the practicality in re-using the SD40 frame 

May I ask, why not? The TP56 only needs the frame-section over one of the trucks,
and you need a way to mount the truck to the loco anyway,
so using the bit of the frame that's designed exactly for the truck you're intending to use sounds entirely logical?

If you cut the frame strategically such that the cut includes a small slice of the 40's fuel tank, it could well take the place of the under-nose-hung fueltank (with suitable reshaping and end-capping?).

I agree with Chris that if re-using parts of the existing frame just isn't happening, a brass frame is the next logical solution...

Happy Modelling,
Aim to Improve,
Prof Klyzlr
Reply 0
The Glorious Tachikoma Active Member 73 posts
The Glorious Tachikoma

patenwriter, Thank you for

patenwriter, Thank you for the suggestion, I have created an account and dispatched a message to the seller. It seems all that would be needed to make a decent model would be photo etch steps. Perhaps I can even find a small-batch source of laser-cut plastic windows. 

 

I'd still like to find a plan-B though in case this falls through. kitbashing using a SW1500 cab means all but two windows on each loco could be grabbed from a set of laser-cut windows for a SW.
Reply 0
The Glorious Tachikoma Active Member 73 posts
The Glorious Tachikoma

Prof, The gear tower that

Prof,

The gear tower that carries the worm gear on the Athearn SD40-2 does not rise very high. I had the idea of simply pressing the Athearn worm onto the shaft of a NWSL motor, or at the least using a solid bushing to link the two, and it does not look like there is enough clearance for a motor.

Cutting Edge Scale Models on shapeways has replied and he has updated HO-scale files on the site for sale.

TP56 Cab/hood: $46

TP56 Steps/Sills: $26

TP56 Fuel Tank: $11

So its more expensive than I thought, I'll be only building one of these at a time as a result. The detail should be better nearly twice as big as N-scale. 
Reply 0
Bernd MRH Author 5,595 posts
Bernd

Project of intreset

I started a scratch-build project of the TP56 several years ago. For those who don't know what a TP56 is here's a prototype picture.

owertp56.jpg 

I just recently did a look-a-like using an Atheran Hustler.

img_2816.jpg 

Using a DVD motor bought off of E-bay I mounted it on a brass scratch-built frame.

img_2817.jpg 

Back to the TP56 I started. I drew up the cab walls and cut them out on my CNC Sherline mill.

24.jpg 

ontwall5.jpg 

For more info on the TP56 check this link out: http://www.tractivepowercorp.com/

Bernd

New York, Vermont & Northern Rwy. - Route of the Black Diamonds - NCSWIC
Reply 0
The Glorious Tachikoma Active Member 73 posts
The Glorious Tachikoma

How smooth is it with that

How smooth is it with that sort of motor? I'm still more interested in using something from NWSL, but if the body is going to cost me a good chunk of change, saving where possible is in my interest. 

If I buy any hard parts off eBay it might be a radio control unit, bypassing DCC altogether and just having a capacitor charge off rail voltage.
Reply 0
Bernd MRH Author 5,595 posts
Bernd

DVD Motor

The motor is a 12 volt 6200 rpm motor. It's very smooth.

If you're interested in R/C check this web site out: http://deltang.co.uk/ I've used his recievers for control and am quite satisfied.

Bernd

New York, Vermont & Northern Rwy. - Route of the Black Diamonds - NCSWIC
Reply 0
Chuck P Prolific poster 1,012 posts
Chuck P

Shapeways

https://www.shapeways.com/product/4WF4SUJE2/tpc-tp56-locomotive-shell-n-ho?li=shareProduct

 
HO - Western New York - 1987 era

"When your memories are greater than your dreams, joy will begin to fade."
Reply 0
The Glorious Tachikoma Active Member 73 posts
The Glorious Tachikoma

Bernd, thank you form the

Bernd, thank you form the source. I think in the interest of cost control a standard universal dcc decoder will be used.do you think it would be worth it to invest in a step-down gearbox since there is a differential in shaft heights or is low speed operation still good? Being that this Has such limited length I still need room for a capacitor as Well as some weight. And nudging by how follow-up that athearn hustler is space will be at a premium.
Reply 0
Reply