Archive.org by itself is a wonderful site to explore. Virtually all of the public domain content that you see people selling on DVD or CD’s is probably there if you look hard enough. Plenty of railroad video content. As with a lot of Public Domain stuff, quality can be poor, but then again it's still worth looking at.
Usually if I have an old website link saved in my Favorites folder that no longer works, I hit the ol’ Wayback Machine and if the planets align properly, can find what I was looking for.
As for 5308, it’s one of my favorites as well. I discovered it along with the 5309 still residing in a scrap yard in Illinois in 1985 and co-chaired the committee that organized the fundraiser to acquire and restore it.
Charlie