The Manchester Evening News reports that the recently opened Metrolink branch to MediaCityUK has been suspended – again. The line came into operation on 20th September but was suspended two days later after a mishap with a set of points. Services were reinstated on 4th October and have run without major incident for the past month, but are now suspended whilst an investigation into an “anomaly” on the new spur takes place.
The Metrolink system currently uses two different types of signalling system. The routes that were converted from railway use standard red and green signals dividing the line into sections. A tram may not pass a signal if there is a tram in the section ahead, as the signal will show red. Once the section ahead is clear, the signal will show green. This signalling is currently in place between Altrincham and Deansgate-Castlefield, Bury and Victoria and the short section of the Eccles line between Cornbrook and Pomona. It has the advantage of allowing trams to travel at higher speeds but has limits on the frequency of trams based on how far apart the signals are spaced and how long it takes for a tram to clear a section.
Trams in the city centre use a different type of signalling – called “line of sight” signalling, the driver can continue as long as the way ahead is clear. There are some traffic lights that have to be obeyed, but these take the form of a line of white bars – horizontal meaning stop, vertical meaning proceed, with extra diagonal aspects at junctions. The Eccles line between Pomona and Eccles already uses this system, and it is proposed to replace the old railway signalling with this line of sight method in order to increase the number of trams that can be operated, specifically between Cornbrook and St. Peter’s Square. The Metrolink trams have better braking systems than trains, so should be able to stop much quicker negating the need for blocks in most locations – though some question marks remain over the Bury line with its bends and tunnels.
This latest suspension in service must come as a disappointment to all concerned. It seems likely that the new line was brought into use in order to meet contractual dates rather than meeting any real traffic flow to and from MediaCityUK. We hope GMPTE and the contractors can get the problems ironed out so that services can be introduced for good.
- Metrolink signalling system at Light Rail Transit Association