Mainline trains
have taken a ride on Metrolink in recent years.
Metrolink hired 3 Class 08 shunters and a Class 60 locomotive from EWS in order to help with the relay of track on the Bury and Altrincham lines.
The ex-BR sections of Metrolink where and still are built and maintained to Network Rail standards, to the point that I believe staff even carry up to date Network Rail literature to assist them with this.
I did have a photo of a Class 60 on Metrolink metals but can't find it at the moment. This proves it did occur, however;
http://www.ews-railway.co.uk/cmsnews...45D244AF8CE%7D
But as EWS states there, there are problems with clearences brining main line locomotives onto the Metrolink network, certainly in the city centre where the OHL is far too low for a mainline loco to fit under (I believe EWS had to bring their locos in via the connection at the ELR).
So there is no chance of fitting a Pacer into the city centre because the wires are too low.
I also don't see a Pacer making it up the gradient towards Shudehill on tram tracks without derailing to be honest.
Non starter.