The book mentioned above "Southern Pacific Lines Standard - Design Depots" by Henry E. Bender Jr. mentioned above would be the best place to start. It can be found on Signature Press's site: [signaturepress.com] and many other retailers of RR related books.


If you're looking for info on depots for a particular line the SPHTS put out a series of books on SP depots a few years back. I've not read these, so cant comment on the contents. Vol 2 and 3 look to be out of print, and prices look pretty stupid high on Amazon. I've seen them for much more reasonable prices at train shows and on ebay.

Vol. 1:
[sphts.myshopify.com]
[www.amazon.com]

Vol. 2:
[www.amazon.com] (at a ridiculous price)

Vol. 3:
[www.amazon.com] (at an even more ridicules price)


Another book that may be of interest was the 4th volume of the SP Common Standard Plans books put out by the SPHTS. Also looks to be out of print...
[www.amazon.com]


Stephen Hayes put out two volumes on CA depots but my understanding is that they are mostly pictorials.
[www.amazon.com]
[www.amazon.com]


Lastly, if you're looking for drawings of specific structures, sometimes books on specific lines will have drawings of some of the depots in them. Most of my collection of books are still packed away since moving, so tough to comment on what ones are good with out getting things out and looking.

Hope this helps,
~Matt