Building a GP9 in Proto:48

[ednadolski]

Here is my project featuring a build of a Red Caboose GP9 in O scale.  I had this kit from a few years back and had put it away since I was having some problems with the drive train.   Recently however I re-discovered it, hiding among a variety of other stored items.  I couldn't resist opening it up and looking it over, and after doing so I realized that it was just too nice a model to let it sit away indefinitely in some box.  So I decided to have a go at fixing up the drive issues and finishing the model.

For the drive train, I was (finally!) able to find the parts that I needed online, and I ended up replacing all the chain and sprockets with better quality components.  I also ended up changing the gear ratios from approx. 1:1 to something like 2.5:1, since my intended use would be low-speed operation.  It took some effort but I finally got the unit running, and I have been very pleased with its low speed performance.

One key feature is the Proto:48 wheelsets which I installed.  These are as close to a true prototype profile as can be made for a model.   The gauge is also a correct scale 56.5" instead of the too-wide traditional scale 60" (1.25 actual inches) that was historically used for O scale (presumed decades ago to be "close enough"...  BTW for that reason you may hear traditional 2-rail O scale referred to a "OW5" in order to make the distinction from Proto:48).  For this model I also have the kit for the trucks which allows them to be narrowed to prototype width.  I was surprised at the difference in appearance that this made.

Since the drive kit for this model came with all-brass trucks, I wanted to modify it to allow all-wheel pickup.   So I fabricated some phosphor-bronze pickup strips and installed them to contact the back sides of the wheels.  You can see the additional wires in some of the pics below.

The model kit originally came with a plastic frame, but I'm building it with the optional machined brass frame.  This is much more sturdy and provides additional weight.  I did have to slightly modify the frame to allow for the larger sprockets that I installed in the drive.  I also installed some additional styrene strips to represent the underframe structural components.

In looking for a prototype, I settled on the Montana Rail Link.  This railroad still has a number of GP9 units in service today, and it is an interesting sight to see these next to the MRL's brand-new SD70Aces.   Besides, I like blue     I'm building this unit as MRL 132, which you can see here and here.   The MRL GP9's have the 'chop nose', so that will be one of the key modifications I will be making to the kit.

Anyways, that's enough words for now.  I'm planning to update this thread as progress continues, in the meantime here are some of my initial pics (including a comparison shot next to a typical N-scale loco).


Drive train with brass frame:




Initial assembly of drive train, trucks, motor, and DCC decoder:




Shell installed on the frame:




Closeup of one of the brass trucks.  The suspension on this thing really works!




Hope you enjoy this!


Ed

[GaryHinshaw]

Cool!  Don't forget the broom when you put her in service:

http://www.railpictures.net/viewphoto.php?id=457012&nseq=50

It looks like these only have the all-weather window on the engineer's side.

[ednadolski]

Quite right!   MRL 132 has a broom on both the front and the rear.

I found a 1:48 scale all-weather window on shapeways.   It looks like the smaller kind, so I might have to splice two of them together to match the proto  (I'm presuming the FUD can be glued).

Ed

[Chris333]

You might model O scale if....  you use wire nuts instead of solder.   

[peteski]

In this scale you could actually power each axle with a miniature traction motor. N scale motors would probably be prefect for that. It would be the ultimately prototypical  PROTO:48!

[ednadolski]

In this scale you could actually power each axle with a miniature traction motor.

NWSL makes a drive called the "Magic Carpet" which is precisely that.  They have it for P:48 as well as OW5, however the cost is $75 per axle, and there are some other caveats wrt operation and capacity.

One thing that I had considered for O scale was the 'dead rail' approach, where the locomotive is powered using batteries and a radio-linked DCC controller instead of receiving power thru the rails.  While a future retrofit is possible, for now I'll be happy to finish this model with the components that I already have

I still have to decide if I am going to use onboard sound or speaker-based sound.   The classic EMD 567 is quite impressive, esp. notching up to full power:

Ed

[Denver Road Doug]

Cool project!

I hope to eventually do some Proto:48 stuff...it'll be a while but my first project will likely be something like this so I'm gonna follow along and try to learn something.   I too like the MRL scheme and have been keeping an eye out for an Atlas 2-Rail MRL SD35.   My premise would be a unit aquired from MRL to handle a shortline/regional that serves a small time coal mine.   Would really prefer an SD9 but thought the Atlas would be a good start until I could get hold of an SD9, which I'm not sure even exists in 2-Rail/Proto:48.   I'm really just starting to learn what is available...and didn't know about the 2-rail "OW5" designation and differences so that's good info.

[ednadolski]

My premise would be a unit aquired from MRL to handle a shortline/regional that serves a small time coal mine.

Looks like the SRY has some ex-MRL units:

http://www.rrpicturearchives.net/locolist.aspx?id=SRY
http://www.rrpicturearchives.net/pictures%5C51043%5CSRY124SRY129e.jpg
http://www.rrpicturearchives.net/pictures%5C51043%5CSRY129SRY124.jpg

I'm afraid it's not a coal mine, but could be interesting if you like car floats.   (And Nanaimo, BC CA is practically right in Gary's back yard!   )


Ed

[ednadolski]

Some progress in the body work department.   Here is the shell with the nose cut down, and with the window set from Des Plaines installed.  I've also filled in a number of areas to try to match the prototype.  As you can see, I still have to finish the part for the numberboards above the cab windows.  This will take a bit of care, to match up to the curved roof line.

The side louvers are another area that needs to be matched up to the proto pics.  I haven't decided on the best approach for this....  I may try sawing out the sections with a very fine jewelers saw and transplanting them at the proper locations.  Archer Transfers does make the decal-resin types of louvers, which would be good except that they don't match up with the rest of the louvers on the shell.

I also need to add small louvers on the battery boxes.  I'll check if the Archers will work OK for that area, otherwise I'll have to scratchbuild something out of styrene.










Thanks for looking!


Ed

[Sokramiketes]

The website still sucks without photos, but if I remember correctly these OSA806's match the Red Caboose louvers.  Might be easier than cutting and moving.

http://www.desplaineshobbies.com/store/product/46887/EMD-GP-E-F-SD-LOUVERS/

[ednadolski]

Yes, that would be a lot easier!   Thanks Mike, I will definitely check those out! 

Ed

[Sokramiketes]

Yes, that would be a lot easier!   Thanks Mike, I will definitely check those out! 

Ed

No problem.  Love the build... I've been tempted since I was asked to CAD the latest version of the brass frames.  Those body kits that DPH ended up with were a sirens call.  It really is some fantastic tooling.

[ednadolski]

Time for an update.   Most of the shell modifications are finished.   The trickiest part was the numberboards over the cab and matching it up to the curved roof.  There are no available parts like this, so I had to make it out of the pieces that were left over from the nose chop.  (I suspect the prototype did the same )

The black louvers are the Des Plaines part, sanded really thin from the back side and cemented into place.  Hopefully the joints will not be too conspicuous after it is painted.  I did add some putty to help blend it in.   The louvers on the battery boxes are the Archer transfers.

















Cheers!

Ed

[Ian MacMillan]

Very nice Ed. I've always wanted to do Proto:48 modeling a backwoods B&M branch line with SW900s and what not. Now if I could just justify the space!

[ednadolski]

Thanks Ian.   from time to time I do wonder, how many N-scale guys might also have a bit of P:48 modeler lurking inside     Anyways, if this build goes well, I'm thinking of doing some kind of small-scope, shelf style layout.  Time will tell.

It would be nice if the P:48 were easier to get started in.   Most of the stuff I see is steam era, so for those who are interested in present-day like myself, it takes an additional effort.

Ed