Theory of Srelativity (SR1)

Just for fun, I created a homemade SR1 mod that adds supercharged engines and attempted to go faster than the speed of light (209,792,458 m/s). However, I found that the speed stops counting at 239,999 m/s. This must be the constant from E=MC2 for simple rockets, since everything is smaller in this game. As we can only mod xml files, I don't think an Alcubierre Warp Drive is possible. There goes Simple Star Trek.