Model Railroading > Broadway Limited MPI SD45 or SD40-M?

I am thinking of pre-ordering Broadway Limited's newly announced MPI SD45s road #9005 and #9019 for my Utah Railway layout. However, the MPI roster refers to these units as model SD40-M. What is the difference visually between an SD45 and n SD40-M?, SD45s have flared ends? Thanks in advance!



Edited 2 time(s). Last edit at 06/28/25 22:05 by RRBMail.

There are lots of online resources discussing the rebuilding of SD45s into SD40-2 internals. I believe these units are classified as SD40M-2 (M referring to Morrison-Knudsen rebuilds). Visually they look the same as SD45 carbodies but the internals are basically an SD40-2 with a 16-cylinder engine replacing the original 20-cylinder. They should be similar to the SP SD40M-2s. 

This may be a useful resource to help you make a decision:
http://espee.railfan.net/spsd40m-2-m.html

 

Alex Wilson
Castro Valley, CA
ApproachAspect's Flickr Photos

I think the Doors on the long hood were rearranged to accommodate the 16 cylinder engine also along with radiators from SD40s.
SD45 had a 20 cylinder.
On the SP SD40M-2 the radiator fan are the same spacing as on GP/SD40 but don't know about the MPI lease units.

edit
Having time & always likeing these units I searched locophotos & it turned up 776 photos of MK SD40M-2 from all railroads. You have to be a member. 

https://www.locophotos.com/index.php  

It really depends on how prototypical correct you want to be but the air brakes don't work ether. Not a big deal to me.
I am temped to get MRL, WC, MPI & HLCX.
 

Tim Hanesworth
Santa Rosa, CA



Edited 1 time(s). Last edit at 06/29/25 10:54 by sp8234.

BLI closed the pre-orders on the 26th. I took a pass on the models because they still had a number of detail issues such as the lack of hoop style cut levers required on units after 1978, and the high cost of the non-sound units with the detail issues. I had been thinking about the SP daylight and MRL units. I doubt anyone will make a fully correct RTR model the MK rebuilds. I have a Athearn RTR model of MPI unit that I did some superdetailing of, but they had a nose stripe issue I had to fix as well.

Ted Curphey
Ontario, OR



Edited 1 time(s). Last edit at 06/29/25 09:46 by funnelfan.

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Some MPI 9000s.

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MPI 9018

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Many SD40-M units have no external changes to their appearance. Engine room doors don't need to be changed just because the engine was shortened from 20 to 16 cylinders. Just meant more working room at the accessory end of the engine. And the SD45 radiators didn't "need" to be replaced either. 

PHall Wrote:
-------------------------------------------------------
> Many SD40-M units have no external changes to
> their appearance. Engine room doors don't need to
> be changed just because the engine was shortened
> from 20 to 16 cylinders. Just meant more working
> room at the accessory end of the engine. And the
> SD45 radiators didn't "need" to be replaced
> either. 

Thank you, you answered my question! 

RRBMail Wrote:
-------------------------------------------------------
> PHall Wrote:
> --------------------------------------------------
> -----
> > Many SD40-M units have no external changes to
> > their appearance. Engine room doors don't need
> to
> > be changed just because the engine was
> shortened
> > from 20 to 16 cylinders. Just meant more
> working
> > room at the accessory end of the engine. And
> the
> > SD45 radiators didn't "need" to be replaced
> > either. 
>
> Thank you, you answered my question! 

Short answer, it depends.  Long answer, depends upon the RR and/or rebuilder.  In some cases, like SP's one and only "SD44R", 7399, on the outside at least, it retained the standard SD45 carbody, but had its 20-645 swapped out for a 16-645.  At a glance you wouldn't know it was basically an SD40-2.  On the other hand, their M-K contracted SD40M-2s, built from SD45, SD40, and SDP45 cores, in the case of the 45-series core units, had the engine cmpartment doors rearranged to line up with the new 16-645, and the radiator cores replaced with 40-series cores, and as mentioned above, had the fan spacing rearranged to match (fans closer together).  Making things more interesting is that there were several different door configurations...my guess is it had to do with which M-K shop did the work and their different ideas on doing things.

On the MPI units, you'd have to look at them unit by unit, but from looking at the images of MPI 9018 that CT97 wsa kind enough to post, its engine compartment doors are different from a stock SD45.  It has 8 tall doors (grouped 2x3x3) vs. 10 on a stock SD45 (2x4x4).  It also shows other changes from its original configuration, like replacement of the sub-base equipment doors and battery doors with lift-off hinge style doors, and Dash-2 electrical cabinet seams behind the cab.  Just some of the features to watch out for on these and to use to decide on whether to model them or not.

As far as the radiators, the 8 row solder-bonded cores the SD45's were originally built with had terrible reliability, prone to frequent leaks at the solder bond to the header. Weibull statistical analysis showed they would only go about 2 years to failure. That's what led to the development of the flat-round mechanically-bonded cores that are now the industry standard. I suspect that if the unit was previously converted to the flat-round cores, MPI would have left them in place since those radiators last nearly forever. If it still had soldered 8 row cores, they probably changed them out to standard SD40-2 6 row solder cores which were much more reliable and cheaper since they didn't need the extra cooling capacity. Early in my EMD career, I sat next to the cooling system engineers and learned a lot.

Dave

PHall Wrote:
-------------------------------------------------------
> Many SD40-M units have no external changes to
> their appearance. Engine room doors don't need to
> be changed just because the engine was shortened
> from 20 to 16 cylinders. Just meant more working
> room at the accessory end of the engine. And the
> SD45 radiators didn't "need" to be replaced
> either. 

This is all based on customer specifications/desires.  CSX allowed us (MK) to used SD45 cores on their SD40M-2 orfder forom 1990 but required that they be complete changed to match the SD40 cores we were using.   15 of the 50 units started life as SD45's but were completely reconfirured to match SD40's.