class 90 in tandem
 

In the gallery is a picture of two class 90s hauling an intermodal.

Why are two needed ?

Is it

A) one is not powerful enough

B) in case one fails

C) using the path to relocate one.

D) none of the above.:)

A and B I think Philip.

It is usually because a single loco (with Bo-Bo wheel arrangement) can have adhesion problems with heavy loads on steep gradients. Freightliner often uses pairs of Class 86 for the same reason.