scope:

Introduction

This Track Work Instruction covers the use of a dynamic track gauge (DTG).

The DTG is a device used to measure how much gauge widens with the passage of a train on the track.

The normal track-measuring gauge can only measure static gauge i.e. when the track is not loaded.

If the condition of the track components is poor, it is possible that the gauge can widen under load. Without the DTG it is impossible to measure this widening.

In poor track, the dynamic gauge (the gauge induced under the passage of a train) can be much wider than the actual measured static gauge i.e. when there is no train on the track.

See also the separate instruction:

TWI 2G061 How to recognise gauge spread