Hi clubagreenie, ( I love that name ), during their normal operating life, both 42 class and 43 class were not allowed to run 2 end leading as the second unit.
They could be run with 2 end leading when in the 3rd position in a triple header set up.
The reason they could not be run 2 end leading in a double header set up is because both classes only had shunting controls in the number 2 end cab and had no rear vision mirrors and the two windows, one at the rear and one at the side, could not be opened.
So if the lead unit failed, the 42 ( or 43 ) if running 2 end leading, could not be used to haul the train.
I only ever saw one set of 43 class locos running back to back and that was on the Newcastle Flier between Gosford and Newcastle.
A little trivia, if you line up a 42, a 421 and a 422 and have a look at the back of the three locos, you can see how the 422 ( both ends ) evolved from the 42, to the 421 and then the final shape on the 422.
