Interviews

The next twenty years

The DfT is part-funding Sheffield’s Supertram track replacement, Baroness Kramer has announced. David Young, deputy interim director general of SYPTE, speaks to RTM.

Sheffield’s Supertram service is undergoing work to replace worn tracks, after more than 20 years of use.

With no re-railing, “a substantial part of the system” would have had to be closed down in summer 2013 because of the risk of derailments on the embedded track sections, which form just over half of the whole network.

The Department for Transport has recently announced £5m of funding towards the replacement, which South Yorkshire Passenger Transport Executive (SYPTE) described as “very helpful”. It has calculated the monetised benefits of the rail replacement scheme at £220m (in 2010 prices), compared to a cost of around £23.6m.

Making the announcement at the beginning of December, transport minister Baroness Kramer said: “An efficient and reliable transport system is critical to any city. The Sheffield Supertram network is an important local feature: it contributes significantly to the growth of the local economy and provides reliable and frequent links to many of the key employment, regeneration and development areas in Sheffield.”

Several alternative measures to extend rail life without full replacement were considered but rejected as “not practical or economic”, SYPTE said, including gauge corner welding, rail head welding, and groove grinding.

SYPTE’s deputy interim director general, David Young, talked to RTM about the scheme, and how minimising disruption was the number one consideration throughout the works.

20 years on

The first contract for the replacement was completed by contractor VolkerRail in autumn 2013, during which 5,450m of track was replaced. This £3.9m contract was for the ‘urgent works’. The second phase, worth about £10.5m, is due to begin in the spring, with the entire programme involving the replacement of 13.5km of life expired rail.

The bid document for the DfT Local Pinch Point funding explains: “This bid refers to the renewal of ‘embedded track’ on the system. This embedded track is made up of a grooved rail held in a slot in a reinforced concrete track slab by a polymer. The grooved rails have worn vertically on the rail head and horizontally on the rail head and keeper. As a result of wear, cracks have started to appear in some areas. If left unattended this would at some point lead to the derailment of a tram.”

Young said: “After 20 years the embedded sections of the tram track are beginning to wear out, particularly on the track with more significant gradient or curvature, or those that have got both heavy curvature and gradient.”

The original rails, installed over 20 years ago, have worn out sooner than expected he said, adding that while there has been some development in the steel technology for these types of rails as opposed to ballasted track, a similar timeframe was predicted for the
new track. SYPTE expects to re-rail the grooved track again in 2033 (and is re-railing the 30-year-old plain track in 2024).

Young added: “To be fair, tram systems in the UK of this nature were very new [when Sheffield’s tram network was built]. Apart from Manchester having one open, there wasn’t really much experience with the sorts of trams we now run.”

And the system has seen 25 trams run over 4.5 million miles since it opened – equivalent to 58 roundtrips to the moon, Young pointed out.

Weathered working

The first phase “went very well” Young said, with lessons learnt around weather-dependent work. Some of the treatment requires a dry environment, with temperatures above a certain level. This influences when the work can be carried out and “puts you at risk of adverse weather”, which explains why the contracts are scheduled over the drier months.

If the track was left to continue degrading, the situation could have become “safety critical”, Young explained. This work aims to phase the track replacement on the areas with highest wear first, and to “avoid being in a position where you have to stop running services on safety grounds”.

He said: “We’ve also got to make sure that the works we do lead to sensible phasing. It’s a combination of pragmatism and prioritising of parts of the network we need to do before others.”

The works come in addition to ongoing maintenance to keep the tram system operating safely and comfortably, including rail grinding: “We’ve never let it get to a position where it’s heavily ribbed and very uncomfortable.”

Tram passengers

Funding has also been provided from the Tram Train project, which is a secondary reason for re-railing. As the bid document puts it: “To allow the Tram Train vehicles to operate on both the light and heavy rail networks, modifications to the track on one or the other of the networks are required to suit the Tram Train wheel profiles. In light of the residual life of the light rail track, the Tram Train project has decided to modify the tram system…it also allows future extensions on the heavy rail network without incurring rail modification costs. The replacement of worn rail with a profile suitable for Tram Train means both problems can be solved at once, reducing overall costs.”

The biggest challenge in this project is to avoid and mitigate disruption to customers, Young said.

“People understand it has to be done; the challenge is keeping people wanting to use the tram even if in the short term you have to divert them onto bus replacement services.When you finish the works you want them to be back as tram passengers.

“The biggest challenge is always minimising the impact on the customers and that’s required a huge amount of work from the Supertram team and my internal team to hide most of the difficult things from the customers so that we’re now seeing them return this year and we’ll hopefully do even better next year and the year after.”

The track replacement will take place in blocks over the spring and summer next year, with a third phase scheduled for the year after that.