How do diesel locomotives operating backwards manage such a speed?

Question

Unlike automobiles that would self-destruct at a prolonged pace.

Answer 1

because they are run by diesel electric motors within each set of trucks and not any drifeshaft type of motive power. it makes no difference which direction the locomotive faces. mechanically its the same in both directions with reversing done by reversing the current or the polarity of the electric motors.

Answer 2

there is no difference to the speed that a Eng can go forward or back ward they are the same you will notice some time that engines (units) one is facing one way and the other is facing the opposite the reason for this is when the train gets to the end of their trip all the engineer does is go to the rear engine that is now the front for the return trip

Answer 3

It's all in the engineering.

Diesel locomotives aren't just diesel, they're diesel-electric.  The diesel engine does nothing but make electricity.  The electric motors actually power the thing.  

Since it's electricity that powers them, whether it's backward or forward, they're simply geared to go either way.  

It's all in the design.

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Answer 4

Diesel-electric locomotives are happy operating in either direction, just as described above, but with an additional attribute.

When considering the wheel arrangement, we have 0-6-6-0, no pony trucks, two sets of six drivers, and no trailing tracks.

Steam engines operated in either direction as well, but were limited when running in reverse because of the trailing trucks used on larger engines to help support the weight of the fire box.  When running in reverse, these so equipped engines could still perform reasonably well.

But, there were many classes of steam engines that had no trailing trucks.  These did not operate in reverse very well with a likely derailment at any appreciable speed.  This is why nearly every terminal had a means to turn the engines around, usually in the form of a turntable, wye or balloon track.

Back to our diesel electric, all weight is distributed on the drivers in relatively uniform fashion, eliminating the need for any pony trucks or trailing trucks, and with the flexibility of electric traction, they operate equally well in either direction.

When you do see a two unit "multiple" diesel consist, they are operated from a single control via "MU" cables, also called "jumper" cables, but not for batteries.  So, even in larger multiple consists it doesn't matter which way the locomotive is facing as the commands it receives is electronically synced up