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LUAS

TRACK & SIGNALS

Despite the obvious differences between the two lines of the Luas network in their geographical, environmental and geometric characteristics, they share the same basic track design standards. The network uses two different types of rail, the S49 Vignole railway rail and the Ri59 grooved tramway rail. These are laid in a variety of ways:

·  Ballasted track: this comprises S49 Vignole rail fastened to 2,200mm long concrete sleepers set at 650mm centres. The sleepers are supported by locally sourced crushed igneous rock ballast;

·  Traditional track: also comprising S49 Vignole rail, this time fastened to discrete, resiliently mounted concrete blocks. The blocks are set into a reinforced concrete trackbed;

·  Embedded track: consisting of Ri59N grooved rail, which is cast into a reinforced concrete trackbed. The rail is factory coated in a 15 mm thick layer of polymer to give primary protection against stray current leakage and also to provide noise and vibration damping. A variety of surface finishes, including granite setts, pattern imprinted concrete, asphalt and grass, are applied as appropriate to the surrounding environment.

 

The minimum track separation is 2,900mm with side overhead line equipment (OHLE) poles or 3,300mm where there are centre poles. In non-segregated areas the twin-track width requirement is at least 6,200mm.

Operational turnback facilities are provided at the termini and at Heuston station. Additional emergency crossovers are provided at a limited number  of  locations  along  both  lines.  Switch

radii have been standardised at 25m and 50m. Only route setting turnouts, which face the direction of travel, are motorised. All facing turnouts are fitted with indicators for safety reasons.

The Luas network will not have signalling in the conventional railway sense. In general, trams will be driven on a line of sight basis, as with any other road vehicle. Special tram signals will be provided where there is a conflict with other road users, e.g. at road crossings, or where different tram movements might conflict. The tram signals will exhibit a horizontal white bar for stop, a vertical white bar for proceed if safe to do so and a small cross for stop if safe to do so. Tram signals and conventional traffic lights will be operated by the same signal controller at each location. There are a total of 48 signalling installations on the two lines being constructed.

 

CONSTRUCTION PROGRESS

Phase 1 Work   The two-year long Phase 1 preparatory work for the Luas project has been successfully completed. The work, which included utility diversions and some significant civil engineering works, was carried out under the direction of the RPA, who undertook the legal duties of Project Supervisor for Design and Construction. Some 232 km of pipes and ducts were diverted during Phase 1 work.

To mark the successful completion of the work, the RPA has published a report on the accident and incident frequency associated with the Luas construction works. This shows that: there were no fatalities associated with the works; there have been no statutory enforcement actions against the works; the accident frequency rates were at worst 50% lower than the national average, with most contractors even better than this; and that nationally, fatalities and all reportable accidents are declining steadily, with Ireland improving on UK rates for the first time.

Phase 2 Work   The RPA expects that all trackwork on Lines A, B and C/C(s) will be in place by Christmas 2003.

Line A (Tallaght-Abbey Street Middle)

Area 1 (Tallaght-Embankment Rd)   Track laying at the Tallaght terminus, adjacent to ‘The Square’ shopping centre, has been completed. Some residual finishing work remains to be finalised, including the surfacing of the platforms at the Tallaght stop.

The platforms at the Hospital, Cookstown and Belgard stops have been completed and surfaced, with equipment such as security cameras and loudspeakers having been installed. OHLE has been erected from the start of the line in the Old Blessington Road to just before the grade crossing at Sylvan Drive. The short section of OHLE across the Sylvan Drive grade crossing has yet to be installed.

Area 2 (Embankment Rd-Red Cow Depot)   The platforms at the Kingswood stop have been completed and surfaced. Security cameras and loudspeakers have been installed. Track laying has been completed through the Red Cow stop and up to the boundary of the depot site. The platforms at the Red Cow stop have been completed and work is in progress on the construction of the large Park+Ride site to be located here.

Area 3 (Red Cow Depot-Davitt Rd)   Track laying has been completed through the grade crossing across the off-ramp from the M50 and is in progress on the ‘tram bridge’ over the motorway. Track laying is also in progress through the grade crossing across the M50 on-ramp and has been completed across the outbound carriageway of the N7 Naas Rd.

Track work and OHLE is in place along the median of the Naas Rd from the Red Cow roundabout to the Old Naas Rd junction in Bluebell. From Bluebell to the junction with Davitt Rd the line is virtually complete, with the final section being laid at the end of August. Landscaping along the median of the N7 has commenced.

Area 4 (Davitt Rd-Grand Canal View)   Track laying has been completed along the length of Davitt Rd, from the junction with the Naas Rd to the Junction with Suir Rd. At the end of August, track was being laid through the Suir Rd. grade crossing and across the bridge spanning the Grand Canal.

On 14 May, contractor’s staff working on the Luas project damaged the ESB Inchicore-Poolbeg 220 kV cable on Davitt Road and disrupted power supplies for a short period. Two of the workers suffered burns and were hospitalised. Investigations into the incident were conducted by the ESB and the Health & Safety Authority.

Area 5 (Grand Canal View-Seán Heuston Bridge)   Track laying has been completed from the foot of the ramp of the Grand Canal bridge to the junction of James’s St and Basin St. The section through St James’s Hospital grounds is carried on a floating slab to minimise the transmission of noise and vibrations to adjacent buildings. The construction of the platforms at the stop at the entrance to the hospital has commenced.

Trackbed construction is well advanced where the line turns northward from James’s St into Steven’s Lane. In Steven’s Lane, the inbound track is complete, with the exception of a small section at the entrance to St Patrick’s Hospital. The outbound track is being laid from the Bow Lane junction to the hospital entrance. New traffic islands are being constructed on St John’s Rd West.

Work on the underground electricity sub-station at Heuston is substantially complete. Construction of the trackbed in front of the station has commenced. Heuston Bridge reopened to pedestrians in May, but track laying has yet to start.

Area 6 (Seán Heuston Bridge-Abbey Street Middle)   Trackbed works are in progress where the alignment crosses Wolfe Tone Quay. In Parkgate Street, track laying is well underway, while work in Benburb St is largely complete, with the track being finished with a pattern imprinted concrete surface. The platforms at the Museum stop remain un-surfaced.

Trackbed works in Queen St have commenced. The section of track through Smithfield, linking the east end of Arran Quay Terrace with Phoenix St North, has been laid and surfaced with granite setts. The platforms at the Smithfield stop have been surfaced and work is in progress on the construction of a plaza between the line and Phoenix St North. Trackbed works in the ‘tram street’ linking Bow St to Church St are well advanced and are underway in the section of Chancery St east of Chancery Place and in Mary’s Abbey.

Track laying has begun in Abbey St Upper. Track is in place from the junction with Jervis Lane to the Marks and Spencer goods entrance. Trackbed construction works in Abbey St Middle are well advanced, as are roadway and footpath reinstatement.

Line B (St Stephen’s Green-Sandyford)

Area 7 (St Stephen’s Green-Charlemont Place)   Construction of the electricity sub-station opposite the Stephen’s Green Centre is virtually complete, with the installation of equipment to be undertaken. Trackbed excavation has commenced on St Stephen’s Green West, with work in progress from the sub-station site to the junction with Harcourt St / Cuffe St / St Stephen’s Green South.

On Harcourt St, trackbed construction is virtually complete between the junctions with Cuffe St / St Stephen’s Green South and Hatch St. Track laying is in progress between Clonmel St and Stable Lane. Between the junctions with Hatch St and Adelaide Rd, trackbed construction works commenced in mid-August.

It had originally been intended that utility companies, such as Bord Gáis, ESB etc., would be able to access their pipes and cables without interfering with the Luas lines. However it has now emerged that the tracks in Harcourt St have encroached into the safety zone for a major underground cable and that the chances of the line having to be close to allow maintenance work be carried out by the ESB have increased.

In Adelaide Rd, trackbed construction works were also commencing in mid August, while in Peter Place work is continuing on laying the inbound track from the junction with Adelaide Rd to the foot of the ramp that will take the line from ground level to the bridge over the Grand Canal. Track laying on the ramp has not yet commenced.

Access to the Charlemont stop from the northern side of the Grand Canal will be by two flights of stairs, one to each platform, situated between the canal and Charlemont Place.

Area 8 (Charlemont Place-Milltown Viaduct)   On the south side of the canal, the access to the platforms will be by stairs and lift and these, along with the electricity sub-station are substantially complete. To allow for increased headroom clearances under the bridges at Dartmouth, Northbrook, Ranelagh and Charleston roads, the trackbed along the embankment section southwards from Grand Parade was raised by between 1 and 3 metres. The new trackbed is being faced with modular concrete units, the outer surface of which is textured to replicate the original embankment walls.

Work on the new stop at Ranelagh is progressing well, with the structure starting to take shape.

Track laying has been completed from just south of the Ranelagh stop to the northern end of Milltown viaduct. The ‘traditional’ track ends just before the Dunville Avenue level crossing. There is a short section of ‘embedded’ track through the crossing and the platforms of the adjacent Beechwood stop, where construction of a small kiosk on the inbound platform has commenced.

Ballasted track starts at the south end of the platforms at the Beechwood stop. It had originally been intended that there would be a turnback siding here, but this has been replaced by a trailing emergency crossover. At Cowper stop, the platform structures are in place but, as yet, surfacing work has yet to start. Surfacing of the platforms at the Milltown stop is well advanced.

At the end of August, the line’s on-track maintenance equipment was stabled immediately north of the Milltown stop. This equipment comprised a ballast tamper built by Fairmont and bearing the serial number RM3594406; a ballast regulator built by Comeng in Australia and a large bogie hopper wagon. The tamper had been sent to Ireland by MVM in the Philippines.

Area 9 (Milltown Viaduct-Balally)   A short distance beyond Milltown stop, the line will pass over the impressive ‘Nine Arches’ Milltown viaduct. Work on refurbishing the viaduct structure has been completed, with a new concrete base for the trackbed having been laid and new railings erected on top of the parapets. South of the viaduct there is a works compound and sub-station. Beyond this the track resumes, but remains to be aligned and tamped as far as the stop at Windy Arbour.

The platforms at the Windy Arbour stop are virtually complete. South of the stop, track laying is complete as far as ‘The Oaks’. OHLE supports and cantilevers, but not the contact wire, have also been erected. Track laying across the Taney bridge has yet to commence.

Substantial earthworks and retaining wall construction have taken place in the cutting southwards from Dundrum towards Balally. Track laying, starting with the outbound line, has begun in this section. The parapets of the Kilmacud Rd Upper bridge have been raised and the erection of OHLE supports has commenced.

Line C/C(s) (Abbey Street Middle-Connolly Station)

Area 11 (Abbey Street Middle-Store Street)   Trackbed construction in Abbey Street Middle is largely complete, except at the exit from Arnotts car park. Track laying is underway from outside the Independent Group offices to the junction with O’Connell St. Trackbed construction through the Abbey St/O’Connell Street junction commenced in mid-May and is well advanced.

Trackbed construction is in progress along the length of Abbey Street Lower, including through the junction with Marlborough Street, where one half of the road is being closed at a time. The first section of track to be installed in Abbey Street Lower was a trailing emergency crossover outside the Abbey Theatre. This will be set into a floating slab to minimise the transmission of vibrations and noise to the theatre.

Trackbed construction work is in progress through the northern opening under the ‘Loop Line’ viaduct, while a short section of track was installed at the junction between Beresford Place and Gardiner Street Lower to allow the realignment of the roadway.

Area 12 (Store Street-Connolly Station)   Trackbed works are well advanced in Store St. In the section of the street from Talbot Place to Amiens St, two single line trackbeds have been constructed, with space between them for the island platform of the Store St stop.

Demolition of the ramp at Connolly has been completed and work is in progress on the construction of the foundations for the trackbed. Work is also underway on the construction of a retaining wall along the front of Connolly station. Trackbed works have commenced at the junction of Mayor St and Amiens St.

Line C1 (Connolly Station-Point Depot)
 The Dublin Docklands Development Authority is planning to raise €22m by 2010 from a levy on future residential and commercial schemes in the North Lotts area of the docklands. The charge, which will be payable by developers, amounts to €2,312 per apartment and €26.81 per square metre for commercial developments built in the area. Social and affordable housing units will be exempted from the levy. The money raised will go towards funding the Luas extension from Connolly to the Point Depot.

 

The remainder of this article appears in IRRS Journal number 153, published February 2004.

Copyright © 2004 by Irish Railway Record Society Limited
Revised: March 15, 2004 .

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