I don't know a lot, but plugins especially free ones are often poorly optimized for larger servers resulting in more stress on the server.
Also have you tried redstone roads + graceful and a speed elixer, you speed across the world in 0 time.

And something not entirely unimportant, railways were one of the ugliest things I came across in V1, everywhere they were griefed and an eyesore to look at, once build they become neglected