Does anyone know of a database or a simple chart or other media, that shows the first manufacture date and years of operation of various locomotives? It would cross reference locos and help in a more realistic choice of gear, for any particular layout, that is suppose to be representing a certain era or time period?
try the diesel spotters guide available from Kalmbach. Ists al diesels, dates of manufacture and who bought them and what quantities. In general railroads kept engines for 15 years due to accountiing procedures so figure a 15 year life.
This site for Diesel manufacturing dates: