by Myrtone
If new rolling stock built for a network or line is a different gauge from the existing rolling stock, there needs to be dual gauge track wherever the old and new fleet share tracks. Dual gauge track may also be needed on a network if some parts get re-gauged while others continue to operate. If dual gauge track between any two standards is not possible, then it is not possible to convert any interconnected network without closing the whole thing, perhaps for an extended period of time.
Also known as Myrtonos