The train speeds, while realistic, are ultimately a hindrance. In order to properly achieve maximum speeds, you’d have to pretty much run a straight track through the length of a medium map. The distance involved would require a high frequency, otherwise the line would see little use. Basically, running high speed trains (specifically the TGV) means having to run them at a loss as vanity projects subsidized by other modes of transport. Is this realistic? Probably, but it’s not fun.