Taking WCML Over Shap as the example and using
http://realtimetrains.co.uk// with it's detailed search, that should get you started on Virgin services at least which are denoted as 'VT'. For instance, looking at the timetable for Carlisle on Tuesday, 1M08 is pathed as a Class 390 EMU, so that one is self explanatory. A bit later on I look at 1S39 and that is pathed as a DMU, so it should be a Voyager.
If you then have Northern Rail services, denoted as 'NT', these are can be trickier, as 2C42 for instance is 'Pathed as Class 150/153/155/156'. In this case, I would then have a Google search of the headcode if unsure, to see which type of unit has been photographed on that service.
Transpennine Express are denoted as TP, and these are trickier still as until recently, they would have been Class 185's, of which there is no official DLC. They are also now using the Class 350 of which I think someone has done a hybrid unit on UKTS? Again, the website tells you which type of traction is pathed.
Freight, again tricky due to the lack of headcodes on sites such as RTT, but I often find that you can look at the service time, origin and destination, and a Google search will again throw up multiple results showing the locmotive and rolling stock.
If you want to go back and do something in the BR Blue period on the same route, it may be worth using the Carlisle Simsig, with a period timetable and the 'simplifier' (F8). This basically allows you to choose your station/junction/yard in the Carlisle area (I think Simsig covers from Gretna Jcn to Shap at least??), select your time of day and the simplifier will list all services in a two hour period that pass/stop at that location. You can then use the timetable viewer (F4) to find the headcode, formation and much more information such as timing points.
Hope that helps.