Thanks everyone for your input this helps a lot.
THanks
listing of diesel locomotives in chronological order as they were produced 1918 to 1989
http://www.urbaneagle.com/data/RRdieselchrono.html
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
Just about every railroad that ever existed has some kind of history book available, although some might be out of print.
My personal bible is J.W Swanberg's New Haven Power, a wonderful resource which lists ever piece of motive power (not just railroad locomotives but tugs and steamships as well) ever used by the New Haven railroad and it's many predecessor lines. Also, the Friends of the Valley Railroad has a collection of photographs which are quite useful for inspiration. You may be able to find equivalent sources for your favorite line.
You might be able to find some references in your local library. Other sources would be:
The historical society / organization for your favorite railroad.
The municipal historical agency of important towns on that railroad's route.
You can also buy generic books on steam or diesel locomotives, or different manufacturer's locomotives.
And remember, Google is your friend!
Connecticut Valley Railroad A Branch of the New York, New Haven, and Hartford
"If you think you can do a thing or think you can't do a thing, you're right." -- Henry Ford
Here is a good basic discussion of diesel locomotives by type and by time frame:
http://en.wikipedia.org/wiki/List_of_GM-EMD_locomotives
Rich
Alton Junction
http://www.thedieselshop.us/INDEXBLDR.html
If you e.g. look up EMD road switchers, you will see that plain GP40s were produced from 1965 to 1971, GP40-2s from 1972 -1986. Which gives you an idea about when they first would have been in service.
Here is another approach that works for many: http://www.lmgtfy.com/?q=EMD+GP40 :-)
Smile, Stein
So i'm very new at model railroading and on a tight budget at the moment. I also do not have the room to buid a layout so I'm basically in the planning/ learning stage for an extended period of time. But i have some issues with trying to figure out what era things are when looking at like buildings and engines, and rolling stock. I kind of figure that the GP-40's and GP-38's are modern day era and such. But is their any quick reference guides out their that could help me? Like i said i'm on tight budget and would like to buy some books and have my eye on some but free is good for me at this point.
ALso i'm looking at modeling a modern day fictitous layout. Any help would be appreciated.