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To overcome icing problems in winter, track heating would be an important safety feature on long hills in Bath. It is possible to heat the track electrically whilst still allowing traction currents to return through it unimpeded. Because the rails are narrow, the amount of power needed is very small compared with the amount which would be needed to heat a comparable length of road surface.

Electrical track heating can be provided by a transformer, having a low voltage centre-tapped secondary winding. If the track section to be heated has the two rails short-circuited to each other at one end, the transformer can drive enough current through the rails to warm them above freezing point.

To allow the returning traction currents to continue flowing, the centre tap of the transformer is joined to the adjacent section of track at one end and the centre of the short circuit is joined to the next section of track at the other end.

The traction currents do not affect the operation of the transformer because they are approximately equal but flow in opposite directions in the low voltage secondary windings. Their magnetic effects on the transformer core cancel out. (The controller should shut down safely in the event that unequal traction currents saturate the transformer core and allow excessive primary currents to flow)

Heated track sections can be joined by connecting the short-circuit of one section to the centre tap point of the next.

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