Problem with Train's speed

Hi, devs! I have a problem with train speed when colliding with some gliders. Unfortunately, the train began to slow down and run before it did the same as driving long. The train makes me embarrassed and the rolling stock bounces at itself and the locomotive’s buffer.

So, I try to test with some videos I’ve uploaded:

So as far as the track inside the world, how I solve problems affects the train’s speed. But also, unfortunately, the train doesn’t make speed on the long track.