A-B-A: why two A units ?

[scottychaos]

simple..because the ABA set is reversable without having to turn it on a turntable or wye..

an ABA set has two "fronts"..it can lead in either direction..an AB set only has one front...you cant very well run a streamliner passenger train with a B-unit in the lead! ;)

Scot 

[dan green]

Hi, I am wondering why the A-B-A diesel engine configuration uses a reversed cab unit and not a cabless B unit at the rear? This seems a standard configuration for Super Chief model sets, was is a standard configuration for the real life Super Chief?