I have an ex LMS Inspection saloon which I want to use on my 4mm P4 layout circa 1962, but am unsure how they were used. The question is we're they pulled or were they pushed? The few photos i have dont make it clear? Did it make a difference if the loco used was steam or diesel? I know that I'f a diesel was used the head code was Iv01 Can anybody help as I am keen to replicate real railway practice.   David