California's Railroad to the U.S. 1861 - 1996

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Model Train Help EBook

Southern Pacific SD40M-2

I haven't modeled one of these yet, so I can't give any firsthand experiences...

General notes:

As you should be aware from reading the SD40M-2 Info page, SP received 133 SD40M-2's from Morrison-Knudsen, with 3 distinct body styles.

The difficulty rating of modeling any of the SD40M-2's, will depend on how accurate you want to be. M-K chopped the 20 cylinder engines down to 16 cylinders, and modified the access doors. The 16 cylinder SD40's probably retained their original door spacing, but the SD45's and the SDP45's will require rearranged doors.

An 'Electrical Cabinet Air Filter Box' (ECAFB), will need to be added to all units, behind the left side of the cab - these are evidently the same size as on the Athearn SD40-2.

All units should have an 81" nose.

The rear radiator fans may also need to be re-spaced. When M-K rebuilt these, they fitted SD40 radiator cores, the fan spacing is slightly less than an SD45. As a consequence, you may also need to fit new or different radiator screens.

The truck sideframes will also need addressing, depending on your needs.


from D. Scott Chatfield:

How close do you want to get? The entire engine and radiator compartments are different from regular SD45s or from the normal-looking SD45 rebuilds M-K made.

A regular SD45 has ten tall engine room doors on each side, eight short doors under the left radiator grille, and seven doors under the right if it has a rear brakewheel.

The early M-K 'SD40M-2s' (these are the modified SD45's) have ELEVEN tall engine room doors, seven short doors on the left, and six short doors on the right. The two I shot (8579 and 8581) have rear brakewheels. Not counting the missing door where the brakewheel is, these still aren't quite in the original GP40 door order.

The rest of the M-K SD45R/'SD40M-2s' that have normal-looking SD45 carbodies have EIGHT tall and EIGHT short doors on the right side, with NINE tall and SEVEN short doors on the left, Good grief. What were they smoking in Boise ?

That leaves the question of what to use. If you want the exact door arrangement, you need to cut the sides out and stock up on Cannon doors. I don't think I'd bother, but it's your model and your call.

The fastest route is to cut out the SD45 radiators, drop in the fan hatch from the Athearn GP40-2, and fill the sides with Cannon's GP40 'waffle' radiator grilles.

BTW, all but one of the M-K 'SD40M-2s' that I've shot from above have 'disk-top' dynamic fans and 'open-top' radiator fans. Not a one has even one disk-top radiator fan.

D. Scott Chatfield

SD40M-2 References for the SD45's:

  • Railroad Model Craftsman October 2000, article on detailing these, starting with a Kato SD45 - by Mike Rose.

SD45's with GP40 rear ends:

Those SD45's that received GP40 rear ends, will require a bit more work in the rear brake wheel area,
and the rear area of the flared dynamic brake blister.

Because they are exSD45's, they have a longer rear flare on the dynamic blister, and they kept
the small vent at the rear of the flare. It is visible in the photo of #8579 and   #8577 at the right.

SD40M-2 References for 8574-8582, 8700:

  • Railroad Model Craftsman September 2000, article on kitbashing these, starting with a Kato SD45 - by Mike Rose.

SDP45 #8691-8696

The six SDP45's, (or SD45M's) whichever you prefer, will require a more extensive kitbash, as no RTR model of these has ever been produced.

You can take a look at my SP SDP45 Info page, for some hints, but bear in mind, that the true SDP45 has a different rear end than the exCR (EL) units.

Either an Athearn FP45 chassis can be milled into submission, or perhaps stretch a Kato or Rail Power Products SD45 chassis - depending on your budget and skills...

SDP45 References for 8691 to 8696:

  • Mainline Modeler, Jul, '89 Page 88, - BN kitbash.
  • Model Railroading, Jul/Aug '84. - Detail Close Up - BN unit.
  • Model Railroading, Apr, '92 Page 21, - Refers to Jim Six article below.
  • Prototype Modeler, Jan/Feb, '85, - SDP45 kitbash - probably an EL unit.

Models for the SD40:Models for the SD45:Models for the SDP45:

N Scale:

  • Kato once made an SD40

HO Scale:

  • Kato is the preferred HO model
  • IHC have re-released their HO Scale model of an SD40
  • Rail Power Products shell and chassis kit.

O Scale:

  • ?

N Scale:

  • Con-Cor
  • Model Power
  • Kato

HO Scale:

  • Athearn
  • Bachmann
  • Kato
  • Rail Power Products shell and chassis kit

O Scale:

  • ?
These will be a kitbash in any scale, or perhaps brass.

SD40M-2 Info page

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Wednesday, May 23, 2001 6:46:18 PM