Rail Temperature

Rail temperature is the temperature of the rail as recorded by an approved type of rail thermometer at site. This differs from the ambient temperature which is the temperature of air in shade at that place, as reported by the meteorological department.

Rail Thermometer

The following are the types of the thermometers for measuring rail temperature:-

i) Embedded type -

This is an ordinary thermometer inserted in a cavity formed. in a piece of railhead, the cavity filed with mercury and sealed. The rail piece is exposed to the same conditions as the rail inside the track. This type of thermometer takes 25 to 30 minutes for attaining temperature of the Rail.

ii) Dial type –

This is a bi-metallic type thermometer, which is provided with magnet for attaching it to the rail. The thermometer is attached on the shady side of the web

of the rail. A steady recording of the rail temperature is reached within 8 minutes.

iii) Continuous recording type –

It consists graduated chart mounted on a disc which gets rotated by a winding mechanism at a constant speed to complete one revolution in 24 hours or 7 days as applicable giving a continues record of rail temperature The sensing element is attached to the web of the rail and connected to the recording pen, through a capillary tube which is filled with mercury.

According to Indian Railway rail temperature is classified into 4 Geographical zones.