To help drive a resort’s revival, engineers transform its historic tram network.
Mungo Stacey reports…
The railways transformed Blackpool into the first seaside resort for the masses. Its attractions these days include the glittering lights of the Illuminations, the Pleasure Beach amusement park and of course the Tower. However, there is a darker side to the town – the Blackpool Task Force recently reported on the acute levels of highly concentrated deprivation, high unemployment, lowest average wages in the region and outdated infrastructure.
A significant regeneration programme has been launched to tackle this overall economic decline and relaunch Blackpool as “a great place to visit – a better place to live” – offering escapism, fun and high quality attractions. An upgrade of the Blackpool tramway is a key part of this drive to improve the economic performance of the town. The £100 million project, approved in 2009, will transform the service, renewing virtually every element of the tramway including stops, track and trams.
The founding fathers of Blackpool had a passion for anything electric (apart from guitars – the Rolling Stones were banned in 1964 for initiating a riot at the Empress Ballrooms). In 1885, just a few years after Werner von Siemens first demonstrated electric traction, the Blackpool Electric Tramway Company began operations, the first such undertaking in the UK. Its fleet history is lengthy, with classics including the double-decker Balloon cars and open-top ‘boats’ of 1934 vintage, the 1985 Centenary cars, the illuminated trams and preserved vintage trams.
Due to their continued operation, the tram vehicles and infrastructure are currently exempt from the 1995 Disability Discrimination Act. However, this dispensation for existing vehicles is set to expire on 1st January 2020. Refurbishing the fleet to provide wheelchair spaces, priority seating and level boarding all within the existing bodyshells would be a tall order.
The alternative was to buy new. This brings a host of other advantages – in addition to meeting the Rail Vehicle Accessibility Regulations, they also have the benefits of modern passenger information systems and improved acceleration and braking. Sixteen new Flexity 2 trams are being provided by Bombardier under a £33 million contract, with the first due to be delivered in June 2011.
There was a strong desire to retain the heritage trams in service and hence three levels of service are proposed. The Bombardiers will provide a ten-minute interval service throughout the year over the full length of the line from Starr Gate to Fleetwood, doubling the present 20-minute interval. This core service meets all the disability requirements, allowing the older vehicles to be exempted and to run as ‘extras’. The Balloon cars will interleave at peak times between Pleasure Beach and Cleveleys along the popular Golden Mile section of the front. The preserved and heritage trams will run ‘on tour’ on special occasions.
Introducing new vehicles has significant ramifications – the stops have to match the door levels and the infrastructure needs modification to suit the longer, wider and heavier trams. Not least, new trams appreciate a new depot. VolkerFitzpatrick is constructing one at Starr Gate at the south end of the route at a cost of £20 million.
To stop or not
All this compliance comes at a cost, which needs to be justified. The business case expects improved patronage to be generated by the better service. Elasticity as applied to runtime is key – a faster service means more people will use it, thus increasing income. By the same token, fewer trams are needed to run a faster service at the same headway, reducing capital and operational costs. The aim is to shave 15 minutes off the current end-to-end timings of 66 minutes. Some of this comes from the improved acceleration of the new trams. Other civils improvements are also needed to track, stops and junctions – these are being carried out by BAM Nuttall under a £25 million contract.
Service planners are familiar with the question of ‘How often to stop?’ People prefer a short walk to the nearest boarding point but provide too many and the dwell time at each reduces the quality of service from end to end. The system had 51 stops over its 18km length which is more akin to a bus network than a modern light rail system. The upgrade works include removal of 14 lesser-used ones.
The remaining 37 are being reconstructed to provide level boarding to the new trams rather than having to clamber up from rail level as at present. This ease of access combined with improved interior circulation space will in itself benefit boarding times. BAM Nuttall is providing platforms 280mm high above rail level and 32m long with surfacing to match the surroundings. The public areas and track crossings will be lit, with Trueform shelters and seating at all stops.
Right of way
Along the prom, the tram runs in its own segregated space and there are few places where road vehicles need to cross it. The sea is beyond! In contrast, the northern end of the route from Thornton Gate to Fisherman’s Walk runs through the towns and, although still on its own segregated alignment, there are many road crossings – most unsignalled.
In theory the trams have right of way at these. In practice the drivers approach the junctions on line-of-sight at low speed, being prepared to stop. This generates a self-fulfilling prophecy as road users see the tram approaching slowly, they assume they can drive across thus forcing the tram to stop. With 20 road junctions on the route, a significant improvement in runtime can be had by installing traffic signals to give the trams priority. Five junctions are being closed, 11 are getting new signals and four will have existing signals upgraded.
BAM Nuttall is designing and installing the junction improvements too. However, its civils agent, Tony Head, has spent more time poring over schematic tram detection diagrams than he might have expected when he took on the job. The traffic signals are controlled by Siemens junction controllers which include self-optimisation algorithms to calibrate the controllers based on measured vehicle flows in service. They take an input from the tram detection kit which is provided by Czech company Elektroline. All junction control is undertaken locally to the junctions.
Ideally the trams should be able to pass through them with minimal reduction in speed. At 50kph this requires detection loops situated some 450m and 300m from the stop line to trigger ‘prepare’ and ‘demand’ signals to the junction controller. In addition the transponders are able to identify whether it is a new or heritage tram, allowing choice of the corresponding deceleration rate within the controller. Two further loops determine if a tram has reached the stop line and when the junction has been cleared.
The first minor junction at Little Bispham was completed in February, allowing extensive testing of the system prior to installation at the remainder of the junctions over the coming winter. This has allowed full testing under a range of service conditions – critical in proving the safety case especially as this system has not been used before in the UK. Initial indications show that the loops appear to be situated just right, with the tram drivers just starting to notch down as the signal clears.
The new trams are the now-common width of 2.65m. However, the route itself was constructed not so long after the 1870 Tramways Act specified a maximum vehicle width of around 2.2m. In more than a few locations the tracks need to be shifted apart to give the necessary clearances between the trams and their surroundings.
From 2002 onwards, the condition of the track had become so poor in places that £12 million of emergency upgrade work was authorised to prevent sections of the tramway having to shut on safety grounds. Between them, Birse and Colas reconstructed 10km of track in the ballasted and segregated areas, achieving modern standards and clearances. BAM Nuttall is replacing the remaining 8km to complete the track renewal of the entire network. These sections include trackslab from Central Pier to North Pier and on to Gynn Square, ballast from Little Bispham to Thornton Gate and the street-running section in Fleetwood.
The trams see highest patronage during the summer season – 85% of the total journeys. The construction contract therefore only permitted work on the central section to occur during the close season from November to Easter. Project manager Mike Grace explains, “Last winter was our first shutdown and we carried out work on two fronts. We’re currently ramping up for this November and plan to work on five fronts. Based on the experience of last year we’re programming to complete over 250m per week.”
Each tramway reconstruction that comes along appears to use a different method for constructing the trackslab. This either indicates that people enjoy reinventing the wheel, that no-one has yet got it right, or that it’s a tricky problem (reader to select based on experience). To be fair, the highway is a harsh environment. For tram engineers it’s the road surfacing that’s the problem and to highway engineers the rails cause all kinds of difficulties. Essentially the issue is the interface between the flexible paving and the rigid rail – the problem is illustrated by the deterioration that commonly occurs around manholes and other ironwork set in roads.
Recent practice for street-running sections has settled on providing concrete shoulders to support the rail and this approach is being adopted in Fleetwood. The section of track there was last reconstructed a couple of decades ago. The existing concrete slab is being reused as a foundation, with 100mm planed off the top to limit the track lift thus avoiding disturbance to the kerb levels and frontages. The wider formation means that a new shoulder is added to the old slab with some kerbs needing to be realigned.
The off-street trackslab is cast in fibre-reinforced concrete. A single-stage pour is used to simplify production, with rails first put into rough alignment on purpose-made temporary steel sleepers before fine tuning the alignment on portal frames at 3m centres. The final 70mm surfacing layer is cast subsequently with an exposed aggregate finish in a nice-looking dark coloured concrete. Duct routes are being installed along the route, both for the tram detection loops and also to give future provision for a system-wide communications network.
Historically, stray return traction currents have not been perceived as a particular issue in Blackpool which is why the existing rails had no insulation from the surrounding ground. The new trackslab is encapsulated in CDM-QTrack rubber profiles, which are a fastenerless embedded rail system providing noise and vibration isolation, but which also offers a degree of stray current isolation. The CDM-QTrack system completely decouples the rail and tram wheel from the road structure.
Initial ground investigation showed that the CBR bearing pressure tests were too low, probably due to a combination of the geotechnical standards required by the design (there weren’t any when the tramway was first laid) and the greater loads imposed by the heavier new trams. In general a cement stabilisation regime was followed, effectively using a giant rotavator, although additional capping was required in places – notably on the first dig which immediately encountered an old sea wall.
The official information leaflet was clearly written by a politician – “Subject to satisfactory progress it is programmed to complete the upgrading to the tramway by Easter 2012”, which is nothing if not noncommittal. The contractor is more upbeat and is aiming to conclude the majority of works by next spring to avoid a third winter period. We look forward to them achieving this goal and, to paraphrase that same information leaflet, to seeing the results of the total upgrade of the tramway to bring the service into the 21st Century.