Steam Era

[glennk28]

I'll second that MR Cyclopedia--has a lot of good basics on how a steam loco works.  Then if you pick a favorite railroad, it probably has a historical society and a lot of books on it that are full of info.   gj

[Rashputin]

    For exactly how steam locomotives work, I recommend, "How A Steam Locomotive Works" by Karen Parker.  It is very well done and covers auxiliaries as well.  I think it's the best fundamental work I've seen.

   Regards

[jbsmith]

Wikipedia!   
http://en.wikipedia.org/wiki/Steam_locomotive

If you want to look up a certain type,,say 2-8-2 mikado,
just type in 2-8-2 on the search area on the left of the screen.

[SteamGene]

A couple of things to remember, though you will find this as you do a bit of research.  As a general rule, a steam locomotive is unique to a specific railroad or system.  Yes, there are the Harrimans and the USRAs, but these are the exceptions.  A NYC Mikado doesn't look like a C&O Mikado, for instance.  Next, just because two locomotives are in the same class, doesn't mean they are identical.  As they got shopped various things got changed:  side mounted air pump (s) got moved to the pilot deck or the smoke box, the loco got a new tender, the bell got moved, a feedwater heater got added, etc.
Another point is that a wheel arrangement had one or more specific names, so saying "2-8-2 Mikado" is redundant.  All Mikes were 2-8-2s.  Some arrangements had more than one name, but there was the "standard" name (Berkshire for the 2-8-4) and the "oddball" name (C&O's Kanawha for their 2-8-4s). 
Gene