Banedanmark launches rail milling maintenance campaign
The second phase of the 2023 rail milling campaign of Danish railway manager Banedanmark is now in progress. Operations began in Funen, where both sections of the Svendborg Line and portions of the main track are under maintenance. The milling train’s mission is to eliminate small cracks in the tracks to prevent them from expanding.
The rail miller typically makes a few visits to Denmark each year. Following its spring tour, which took the hefty 155-ton train all around the country, it is now time to launch the autumn season. Once again, the objective is to address cracks in the tracks on Funen, Zealand, and Jutland. These minor cracks in the tracks were initially identified through inspection with measurement cars. Now, the Rail miller is deployed to grind them away.
“When we grind the tracks, we extend their operational lifespan. The milling wheel effectively eliminates the cracks, thereby reducing the risk of rail fractures that tend to occur during winter when there are significant tensile stresses in the tracks”, explains Pernille Skovrup, maintenance manager at Banedanmark.
The rail miller is capable of removing more than a millimetre of rail per pass. It typically requires 1-3 passes to eliminate a crack in the rail, and as a result, the rail miller moves back and forth at the same location until the crack is completely eradicated. The noise level during its operation remains relatively moderate, and the rail miller swiftly progresses due to the multitude of cracks it needs to address over the course of a single night.
Slow and steady wins the race
During a night’s worth of work, the rail miller can grind up to three tons of iron from the rails. Following this, the iron undergoes a meticulous examination, sorting, and processing phase before being prepared for recycling. The cracks along the rail’s edges are detected during the measurement train’s spring journeys. The measurement train employs eddy currents to identify surface cracks and ultrasound technology to pinpoint internal cracks within the rails.
Moving at a deliberately slow pace, the rail miller operates at speeds as low as 400 metres per hour. Equipped with two milling wheels and one grinding wheel on each side, the grinding train ensures precise removal of the cracks, with millimetre-level accuracy. Measuring nearly 44 metres in length and weighing 155 tons with grinding residue, the train is operated by a team of international experts. A Danish pilot, well-versed in the specific routes, is also part of the team. The train’s top speed is limited to 70 kilometres per hour when tasks on Danish rails travelling between.
To minimise disruptions to rail traffic, the rail miller conducts its operations at night and undergoes cleaning and preparation during the day. Skovrup: “In the future, as more trains are anticipated on the rails, it becomes increasingly crucial to maintain an efficient maintenance regimen that can be carried out with minimal interference to traffic. Hence, the decision for the Rail Grinder to operate during nighttime hours”.