It's possible to have different gauges at the same station, requiring just a change of train rather than an additional bus transfer. And some systems are variab

It's possible to have different gauges at the same station, requiring just a change of train rather than an additional bus transfer. And some systems are variable gauge, allowing for the same train to operate on different systems. https://en.m.wikipedia.org/wiki/Variable_gauge https://en.m.wikipedia.org/wiki/Variable_gauge