I have a lot of old mainline locos which have been stored for about 20 years. I am now working on a new layoutand propose to use as much of the old stock as I can. The Mainline locos look to be in good nick, although I believe the steam locos can be a little fragile. However, they never did get a lot of use when I was a kid, because I favoured the diesels in those days. Is there anything I should do, in terms of servicing them, before firing some electricity through them for the first time in 20 years, all tips welcomes