Back-Dating A Pair of Atlas SIlver Series GP40-2's to Plain GP40's is a free Model Railroad Discussion Forum and photo gallery. We cover all scales and sizes of model railroads. Whether you're a master model railroader or just getting started, you'll find something of interest here.


Lazy Daydreamer
Hello Forum denizens, I promised my friends in the Coffee Shop that I would write a separate thread about a project I've been working on-and-off over the past four months: Taking a pair of mothballed HO scale Atlas GP40-2's and kitbashing them into "dash-nothings", i.e., regular GP40's that I could use on my 1969-72 era B&O layout.

It all started late last spring, when I made an impulse purchase of a NOS Atlas GP38 from an eBay seller - because it had the early-style dynamic brake blister that came on EMD's earliest-shipped units in 1966, before they they shrunk them down to accommodate the large sand filter enclosures. I was sharing about this in the Coffee Shop thread when a member named Paul, a.k.a. "kjd", mentioned that Atlas sells replacement dynamic brake hatches in both the old and new style. This little tidbit of knowledge would really come in handy in the near future (thanks Paul!:cool:).

A day or two later I was searching for something in my attic when I caught sight of a pair of GP40-2 models leftover from my days of modeling CSX.

(I tried to post a link to a seller's photo of a unit identical to one of my own, but got a "403 Forbidden" error message when I tested the link...:mad:
Sure wish I would have thought to photograph my own units back in the days when they were active...)

(to be continued...)


Lazy Daydreamer
Even though they were in perfect operating condition, my GP40-2's would obviously be out of place running on my pre-Chessie B&O layout. I couldn't just strip them and repaint them for B&O because, in addition to the sight glass on the right side of the long hood, they had different-sized dynamic brake blisters - standard length on one side, extended on the other.

Then I had a "lightbulb" moment: If I ordered some of the early-style GP38 dynamic brake hatches from Atlas, I could remove the dash-2 hatches and substitute them with the replacement hatches (along with some other detail parts from Cannon & Co.) and build credible-looking GP40 models.

I went ahead and ordered 4 of the Atlas dynamic brake hatches, plus some Cannon & Company tubrocharger exhaust stacks to get started. I soon discovered that I would need additional detail parts for a credible conversion, such as early-style radiator fan grills [Atlas] and inertial air filter hatches [Cannon].


Here's a bill-of-materials:

Atlas P/N 910825 GP38* early-style Dynamic brake hatch Qty: 2
Cannon P/N TH1952 EMD Turbo Hatch - '40' Series (set of 2) Qty: 1

Atlas P/N 890240 Radiator Fan Grill (set of 4) Qty: 2

Cannon P/N FH1353 Inertial Filter Hatches for GP's and SD's (set of 2) Qty: 1

Atlas P/N 890300 Blomberg 'B' Truck Assembly** (set of 2) Qty: 2

* I ordered GP38 hatch covers because I was also kitbashing some GP38's in addition to GP40's, and I didn't see any GP40 DB hatches (p/n 890295) on the Atlas Parts catalog web page.

** I originally also ordered some Atlas brake cylinders to replace the single shock absorber on each truck, but later abandoned that idea (more about that later).


Lazy Daydreamer
With all the materials finally on hand, I proceeded to strip off the factory-applied CSX paint. First thing after that, I milled-off the inertial air filter hatches. The filter hatches on the original GP40 were longer and had a lower vertical profile than the almost-square shaped hatches on the dash-2 models, so they had to be replaced.

I was taken aback when I found that the replacement GP38/40 radiator fan covers were only the grilles without the base. Luckily, the dash-2 grilles were easy to pop-out and replace with the earlier-type replacement grills - after surgically removing their outermost rings:

For the D/B hatches, I cemented-on a Cannon & Co. EMD turbo stack on each of the GP38 hatches and - voila! - GP40 hatches!

Finally, after Dremeling-off the original dash-2 inertial filter hatches and smoothing the surfaces, I cemented-on some Cannon earlier-style hatches like these:

...and here is what the upper body shells looked like before being painted:


I kept the frame covers (walkways) separate and painted-on the Enchantment Blue coloring by hand, because their sill stripes were already the perfect shade of yellow [for B&O/C&O] and had the EMD builders' plate decals on them.

My next step was to airbrush the upper body shells with a homegrown blend of 2 parts Tamiya Royal Blue with 1 part Tamiya Red, to get what I thought looked like C&O Enchantment Blue. After allowing a week for the paint to cure, I applied Microscale decals. It was immediately after this, when I proceeded to paint & weather the truck sideframes, that I realized [from careful study of the prototype photos] that the Blomberg 'M' trucks that came with the original stock GP40-2 were missing outboard brake shoes - a highly visible spotting feature on early GP40's. I decided to just replace the trucks in their entirety, rather than try to mess with disassembling each truck and trying to put the two halves back together with my tremor-afflicted hands!


Lazy Daydreamer
After I had applied the decals, I airbrushed the shells with watered-down Tamiya Flat White paint (10 parts thinner to 1 part paint) in order to achieve the faded appearance of dark blue locos that had been in service for a few years. Then I covered them with a layer of Dullcote and, once that was sufficiently dried and cured, used Pan Pastels to create the dust splashes and exhaust soot streaks. With all the trial-and-error wiring misadventures I experienced while swapping out the trucks, I forgot about trying to photo-document the remaining steps of the project; I'll just have to fast-forward to the photos of the finished products.

B&O #3698 (formerly CSX #6358):



B&O #3728 (formerly CSX #6015):




Lazy Daydreamer
Thank you all for the kind comments! 👍 It was a fun project, even though it took me way longer than what I initially anticipated. I just couldn't bear the thought of two Atlas 59-ft geeps in good operating condition being left unused...


Active Member
I guess it's a little late now, but the cabs and battery boxes are also different between -2s and non-2s.

Affiliate Disclosure: We may receive a commision from some of the links and ads shown on this website (Learn More Here) is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to - An online railroad bookstore featuring a curated selection of new and used railroad books. Railroad pictorials, railroad history, steam locomotives, passenger trains, modern railroading. Hundreds of titles available, most at discount prices! We also have a video and children's book section. - An online model railroad bookstore featuring a curated selection of new and used books. Layout design, track plans, scenery and structure building, wiring, DCC, Tinplate, Toy Trains, Price Guides and more.