Okay, thanks!

Yeah, sure. The accelotron rails are locomotive bunker systems. You're supposed to place the starting part first, which has the icon of the rear end of an arrow, the fletching, and then at the same height, place the front end of the arrow of the same direction, which has the more obvious icon of the front end of an arrow, the tip. Then, between the starting and ending positions, there will be an area, the 'rail', where all actors and dropped weapons and stuff will be snapped to a certain vertical position, and horizontally they will be accelerated in the direction of the arrow.
Two equal and opposite accelotron rails are handy for fast yet safe locomotion.

The speedometer just reports the speed of stuff that goes through it. It's supposed to be text on the screen, but I think I never bothered to get that working, so you have to open the console to read the results.

I don't get what is"Accelotron Rails" and "Speedometer". Can you explain it a bit?