Innovation Continues in Track Maintenance Machinery

Europe’s rail infrastructure authorities are under pressure from operators to improve the track bed on which trains run. This factor is pushing infrastructure managers to adopt increasing levels of mechanization, with high-output machinery that will cover a large amount of ground in a short time at a premium. Some prime examples of the trend can be seen on Railtrack’s West Coast main line in the UK, where major renovation work is underway.

As part of the £5.4 billion modernization project, the track on the fast lines all the way from London to Crewe is being renewed.

On the West Coast route, Railtrack is moving to UIC60 rail, the heavyweight profile used on Europe’s main lines. New rail is dropped by the side of the line ready for the arrival of the track renewal train (TRT). The TRT carries a supply of new sleepers with it. It unclips the old rail and shifts it out to the side, takes out the old sleepers and disposes of them in wagons in the TRT consist, retrieves new sleepers and drops them in position, and finally clips in the new rail.

To work in conjunction with the TRT, Railtrack has purchased two Medium Output Ballast Cleaners (MOBC) from Plasser&Theurer of Austria.

The UK is at present proving to be one of the most productive territories for the permanent way machinery manufacturers. Sale of tampers, for example, is running at a brisk pace. Balfour Beatty has taken delivery of two 08 Unimats from Plasser&Theurer, with an 09-3X coming this spring. The’X’ in the designation stands for ‘Express’: new features of the 09-3X are two three-sleeper track tamping units which enable three sleepers to be tamped in one operation. Each tamping unit consists of two separate parts to be able to work on tracks with irregular sleepers spacing, if required.

Stoneblower machines are also sold well. The Stoneblower works by measuring the alignment of the track to an accuracy of 0.5 mm and injecting stones to fill any space beneath sleepers, so as to provide a smooth surface. Traditional tamping methods tend to destroy the ballast, but Stoneblower leaves the ballast largely unharmed and therefore maintenance is more long lasting. An allied advantage is that the track does not tend to ‘remember’ the same poor top and line as it had before treatment, as can happen with conventional tamping.

The Stoneblower works with a crew of three. First, a pass is made over the work area at a speed of up to 15 km/h while the machine assesses the state of the track and calculates where stone needs to be injected. Then the machine reverses over the stretch to do the work, normally tackling two sleepers at a time. The output rate is about 350 m/hr.