I may well be out of luck here, but I have several old (I'd say 1960's or 70's at best) steam locos - Varney, Rivarossi - which are in fine running condition except that the valve gear is long gone... I like them because they have very, very heavy diecast bodies and pull like a Son-of-a...well... they pull great. Any idea on a source to try and replace the missing valve gear?