I'm not sure how to format this since I don't post a lot. But I'm pretty sure I found A way to Boost Sonic's speed on grind rails, It's really simple All you have to do is switch from rail to rail and mid switch boost. I'm not sure if something like this is In other boost games but I was messing around and did it, if this is a commonly known thing I apologize for posting this.

From what I've been reading in the Frontiers discord, boosting in Frontiers simply multiplies your speed. I'm not sure if its known or faster exactly, if you post in #science in the Frontiers discord you may be able to know for sure