Rapid transit track gauge

Okay so imagine you have a toy train set with lots of track pieces. Now, each track piece needs to fit together perfectly so that the train can ride on it smoothly, right? That's kind of what we're talking about when we talk about track gauge.

Rapid transit track gauge is like the special size of track that trains and subways use to travel quickly and smoothly between stops in big cities. But why does it matter what size the track is? Well, think of it this way - if the toy train tracks were too far apart or too close together, the train would either wobble or get stuck.

The same thing applies to real train tracks. If the gauge is too wide or too narrow, the trains won't be able to run as efficiently or safely. This is why different parts of the world have different track gauges. For example, in Europe, they use a narrower gauge than in the US.

So basically, rapid transit track gauge is just the special size of tracks that are made to fit the trains that run in big cities, so they can ride smoothly and safely between stops.