(01 May 2014, 9:04 am)eezypeazy wrote As far as I can tell, there's little rhyme or reason as to whether you get a 156 or a 142. The only runs that are (almost) guaranteed to be 156s are the Scotrail trains to/from Glasgow.

I've recently observed a 142 being allocated to the once-a-day Carlisle - Middlesbrough run!

Whenever I have used that particular timed train, it has always been a 142.
Unless it drops out somewhere and picks up a run to Carlisle, then this branded 156 will be away from its home turf for a few days - as the diagram it is on, doesn't allow it to get back to the North West.

A 142 doing a Middlesbrough - Carlisle run, isn't rare at all.

(01 May 2014, 11:39 am)eezypeazy wrote If Andreos is contemplating a Sunday outing, then I notice there's a Carlisle to NOTTINGHAM through Northern service leaves Carlisle at 1520 via S&C, Leeds and Sheffield. Is that the longest possible Northern bash without a change?

Most probably!
Any idea on prices?

Didn't even realise Northern or any other operator ran between Leeds and Nottingham.
Always changed at Grantham or Sheffield/Chesterfield when going to/from Nottingham on the train.