How do you imorove train speed in rail roading?

Instead of increasing train speeds, another alternative is to increase the capacity of a stretch of rail (how many trains can occupy it at any time). Trains have to be separated by a certain interval since they need time to stop in case of emergency, and they don't broadcast where they are, so a following train can't see something ahead of them until it's too late. Railroads installed signals that will tell the trains that there is something ahead of them, and to restrict their speed the closer they get. However, the signals are located every few miles along the tracks, so trains are usually separated by about 10 miles or so, since if they get closer, the signals keep telling them to slow down. If you place a signal readout in the locomotive (this is called Cab Signals), instead of on lightposts every few miles, the train crew has a more rapid readout of track conditions and can adjust their speed sooner, so trains can run closer together, which means more trains on the same stretch of track, so you get more cargo hauled without making any track changes (other than installing the cab signal broadcasters, that is).

Well leveled, well ballasted, and welded rail. Rail lines separated from grade (no crossings with roads, walkways). Dedicated rails for passenger traffic. Tunnel where possible to avoid curves and climbs. Improved signaling and tracking. I know these are points from the California High-Speed Rail Authority.

1. maintain the rails very well 2. straigten out curves to a radius above 3000 m 3. avoid climbing mountains by tunnels 4. using trains like Talgo (www.talgo.es) 5. invest a lot of money 6. look at the examples in Europe and Japan

Well-maintained level track.