Where can you find loco dates

[Steve_F]

This could be what you are looking for...

 http://www.urbaneagle.com/data/RRdieselchrono.html

[nanaimo73]

This site is pretty good for older EMD/GMDs-
http://www.trainweb.org/emdloco/index.html

You can also look on this site for a specific locomotive, most are listed-
http://www.rrpicturearchives.net/

[ndbprr]

Yes. You can buy the Diesel Spotters Guide from Kalmbach.  It not only lists that information it tells you who the original owners were, how many they had and what year they bought them as well as the spotting features.

[BATMAN]

This might not be exactly what your looking for but it could possibly answer some of your questions.

http://www.trainweb.org/galt-stn/cproster/main.htm

[U.P.5714]

 Is there a book or someplace on the web were one can find what loco's were built in what year? I know you can check by type of unit, I was just wondering if there was a place for one stop shopping?? Mainly like what units were in the 70's, 80's & 90's without hunting all over for the dates when they came out.