[zfneytgi] Train pull or push

We consider the differences between a train in pull formation and push formation in the event of an accident.

In the "normal" pull formation, with the engine at the front, suppose the front car, i.e., the engine, derails, perhaps due to something wrong with, or on, the track. After derailing the engine no longer has a grip on the track so is no longer supplying additional energy into the accident. Of course, the unpowered trailing cars still have momentum which will cause them to collide and pile on top of each other.

In "push" formation, the engine is at the back and pushes unpowered cars in front of it. I've seen the MBTA commuter rail run trains in this formation. Suppose the front car, an unpowered car, derails. The rear engine does not derail immediately so maintains a grip on the track. Until the operator shuts it off (though this could be nearly immediate with a dead man's switch at the front), or the effects of the derailment reaches the back causing the engine to ultimately derail, the engine continues to plow forward, supplying additional energy and destruction into the accident.