There is the parameter to replace various kinds of rails from nutracks.
However in some cases such as when playing with 2cc or japanese train sets, monorail/maglev could also benefit greatly from replacing the rails.
Particularly for example in alpine climate where you need to replace the tracks with some railtype newgrf. Then the only option is transrapid track set for monorail, and SMITS for maglev. It would be great if there was also the option of "normal" rails for this case. :)