Hi Heather.  First of all, you are posting in the wrong place!  Since you mention L&Y, I think you are thinking of older vehicles - "pre-grouping", which is pre 1923.  Also, before anyone can give sensible answers, you need to say what scale of models you are looking for: 0-gaige (7mm), 00 (4mm), N (2mm), or whatever.  You seem to have specific types in mind "brass and plastic", coarse (?) steel wheels and so on.  Try posting in "Modelling Questions, Help and Tips" or, perhaps, the Pre-Grouping area of the Forums, and provide more detailed info. and someone may be able to help.