Carlisle is not as busy as previous years and can go hours during the week with no freight movements, still attracts spotters though!
Roughly guarenteed to be seen(depend on the time your around) will be.
Units........
Class 153, Northern on Leeds
Class 156 Northern on Newcastle's, Cumbrian Coast & ScotRail on Dumfries/Glasgow.
Class 158, Northern on Leeds.
Class 221, Virgin on Glasgow/Edinburgh to London (via Bham)
Class 325, on Postals.
Class 350 TPE on Glasgow/Edinburgh to Man Airport
Class 390, Virgin on Edinburgh/Glasgow to London
Locos...
Class 37,DRS on Cumbrian Coast.
Class 57, DRS on Thunderbird duty.
Class 66, Freightliner, DBS, DRS, GBRF various sporadic freight.
Class 68 DRS, Cumbrian Coast.
Class 70, Colras, on tanks.logs
Class 88, DRS on Liners
Class 90, Freightliner on liners.
Class 92, Caledonian sleeper on sleepers.
Obviously a broad overview.
With the rail treatment season starting a few more DRS locos will be around on those.