I reckon that's pretty near the mark Alan. From what I've been told by my dad, my grandad worked at the Saltend/BP branch so I guess it was a case of making sure that trains were made up in the right order.
I'm sure that all of the members would like to hear of your experiences as a fireman if you would care to post them up for us.
Have a look at this thread...
http://www.railwayforum.net/showthread.php?t=305
Ignore the 'trainspotting' bias at the beginning, it's also for memories of people such as yourself whose recollections are invaluable.
