Buffer Car

[Sawtooth500]

I know trains like ethanol trains need a buffer car between the crew and tank cars - commonly a hopper. 

So if you got 3 locomotives, why can't the rear locomotive be the buffer?

[BaltACD]

Locomotives having internal combustion engines are a source of 'fire'.  A Buffer car(s) is not a source of fire (note - Mechanical Referigerator cars can not be used as buffers either).