If you are interested in playing a rail only map for generations, I just made one called RAILME. Actually I made it for pkarena, but made a few changes so it can be also played in generations. It is a small 1 vs 1 DM map where you respawn with the railgun only. I have played it with three nightmare bots, one bot for each of the classes with railgun or snipegun (earth) and it is just that, a NIGHTMARE!. Obviously, you should only use the classes that have the railgun. DOOM and Slippy would find it very hard to survive.
Note: You also respawn with a hook, sorry but like I said it was designed for pkarena where we use the hook not only as in it's regular use, but in version 3.0 by hitting gaunlet key twice, it gives the gaunlet to the top of the hook and we can slash people (tongue slashing) :=)
http://www.geocities.com/Area51/Nova/2704/news.htmlWARNING: I ain't no serious mapper, don't expect a Carmack or Romero level, download RAILME (1.4 Mb) with caution :=)