EMD SD45X #4202

I would hope so, as their tractive effort at MCS was identical.

RWM

Which is why the 3600 HP SD45 didn’t much in it’s Dash 2 form, but the subsequent SD50 sold a ton.

The SD50 balanced the increased HP with an increase in TE. (D87 TMs = more amps, Super Series = more adhesion)

There were seven SD45Xs built between June, 1970 and February, 1971. Six were sold to Southern Pacific while one (4202) was retained by EMD. All of SP’s units had been disposed of prior to 1980.

Santa Fe never owned a SD45X.

It was EMD #5740, the first built that was retained by EMD. The SD45X Demonstrator EMD #4202 became Espee #9504.

GP40X?

You must be thinking of the former ATSF-SD45-2s that have been rebuilt as SD40-2Rs and repainted into the new BNSF paint scheme.

A third SD45X (9500) survives in its rebuilt form still in SP paint.