Cold Weather Patrolling
by Rajeev Shrivastava
In sections having long welded rails (LWR), cold weather patrolling is done when the rail temperature is less than Td-30°C (Td = destressing temperature, which is typically 40°C or so). The schedule of patrolling and sections to be patrolled are laid down beforehand, based on the temperature records maintained for the section. Normally, such patrolling starts around the first half of December and continues until February. Patrol charts are prepared and issued, detailing the movement, direction, and timings of the patrollers. Patrol books are issued which are supposed to be countersigned by the ASMs, Cabin men, or Gatemen as the case may be. The books are exchanged within the gang beat from end to end, every time the patrollers meet at the junction of their beats.
On single line sections or where only one 'road' has LWR, one patrolman is given a 2km length to patrol. On double line sections, where LWR exists on both 'roads' one patroller is given 1km of both the lines to patrol.
The patroller walks over his beat slowly along one rail in one direction and on the other rail in the return direction. On double lines, he repeats this procedure alternately on the Up and Down tracks. He watches out for rail and weld fractures. He also keeps an eye on the gaps at the switch expansion joints at the ends of the LWR. In case the patroller notices a fracture or the gap at the SEJ is seen to be greater than the designed maximum gap for the SEJ1, he suspends the traffic and protects2 the line. After protecting the line, he tries to inform the key man, gang mate, permanent way mistry, or permanent way inspector (PWI). The patroller is authorized to make emergency repairs3 if he can and to restore the traffic at a speed restriction4. The temporary and permanent repairs5 are done by PWM/PWI.
A cold weather patroller carries following equipment:
- 10 fog signals (detonators) in a tin case
- 2 tri-color hand signal lamps
- 1 match box
- 2 red flags and 1 green flag
- 1 three-cell electric torch
- 1 number plate and staff (to display his number to the train)
Normally patrolling starts at 2300 hours and continues until 0700 hours. The minimum rail temperature is known to occur around 0300-0500 hours and most fractures occur during this period.
- 120mm or 190mm as the case may be, depending on the design of the SEJ.
- Protection is done by deploying fog signals (detonators) on either side (in single line) or at the rear (in double line) of the fracture, at prescribed distances and displaying a red flag or light towards the approaching train. These detonators explode beneath the wheels and the sound warns the driver to stop.
- By clamping the fracture, using a pair of joggled fish plates and clamps. Spare joggle fishplates (color painted for easy identification) are tied to the track, at every kilometer.
- Typically first train passes at stop dead and 10km/h and subsequent trains pass at 20km/h after emergency repairs. Temporary repairs enable trains to pass at 30km/h.
- Temporary repair means that a 6m rail piece has been inserted in the track and both ends have been clamped. In permanent repair, the joints are welded.