BYLINE: Eric Chemineau and Kenneth Herring*

ON MARCH 10, State Railway of Thailand officially inaugurated the third track on a key section of its Northern main line (RG 2.00 p72). The line had been formally opened on December 5 1999 to mark the Sixth Cycle Anniversary Birthday of HM King Bhumipol Adulyadej The Great, but trains had been running on part of the new track since November 26.

The so-called Track Doubling Package 1 covers the first 60 km of a 1029 km programme approved by the Thai government in 1993. TDP1 and TDP2 mainly involve works to increase capacity on routes radiating from Bangkok (map). The route runs from Klong Rangsit on the northern edge of the capital’s suburban area (where extra capacity is due to be provided by the BERTS project) to Ban Phachi Junction, the divergence of SRT’s main lines to Chiang Mai, Nong Khai and Ubon Ratchathani.

Detailed engineering design was carried out by P&A Group, formed by Pacific Consultants International and Asian Engineering Consultants Corp Ltd. Main contractor was a joint venture of Italian-Thai Development Public Co Ltd and Cogifer TF of France, which signed a contract worth 3·2bn baht with SRT on May 29 1997. P&A Group was retained as project consultant. Start date was agreed as July 1 1997, with the work to be completed within 28 months.

TDP1 involved the laying of an extra 1000mm gauge track from Klong Rangsit to Ban Phachi, including station loops and sidings, connections with the existing tracks, and modification of signalling and telecommunications equipment.

Earthworks included over 1million m3 of fill, plus 13 concrete and 11 steel bridges with spans ranging from 6m to 31·7m. At the southern end, 39route-km of concrete piling was needed to support the widened embankment. Two station buildings and 23 platforms were also provided.

Modifications proposed by the contractor included a new alignment reducing the number of curves, smoother gradients, a new fastening system for the steel bridges and the use of junction welds between different rail sections. Under Project Manager Pipat Lorach, 1250 people were employed on the project, including 250 responsible for trackwork.

Specifications and suppliers

For the main track and connections with the existing tracks, BS100 continuously-welded 50 kg/m rail was laid on concrete monobloc sleepers, attached by elastic fastenings. Welded turnouts with manganese crossings and flexible tongues were installed on concrete bearers. On steel bridges, galvanized steel sleepers were fixed to the deck, with two layers of insulation to absorb noise and vibration.

Continuously welded BS80 40 kg/m rail was used for the sidings, again with concrete sleepers, but with jointed turnouts on timber sleepers.

In total, 6700 tonnes of BS100 rail and 1300 tonnes of BS80 rail were purchased from Japan. Over 147000 concrete sleepers and 10000 bearers (varying from 2m to 3·4m in length) were produced locally at ITD’s Wihan Daeng plant in Saraburi. Around 160000 sets of DSA clip fastenings were supplied by Stedef.

ITD/Cogifer subsidiary ATO assembled 150 main line turnouts at Wihan Daeng using tongues, stock rails, monobloc manganese crossings and guard rails supplied by Cogifer Industrie, which also supplied glued insulated joints for the BS100 rail. Half of the 30 siding turnouts made of BS80 rail were assembled by ATO, and the rest by SRT workshops. An ITD quarry near Wihan Daeng supplied 160000m3 of rhyolite stone ballast, and 4500 welding kits were supplied by Thermit Australia. Mechanical insulated joints for the welded rail came from Exel of Finland. Timber and steel sleepers were bought locally, and the level crossing panels were manufactured at Wihan Daeng.

Short possessions

After the concrete sleepers were laid along the new embankment, the first ballast was put in place and compacted using a paver. Sleepers were then positioned at a 600mm spacing, using a crawler shovel equipped with a frame beam. Three on-site gas pressure units welded eight 18m rails into 144m sections. After geometric and ultrasonic inspection of the welds, the sections were moved by trolley and positioned on the sleepers. Fastenings were then installed, and the sections Thermit welded together.

Ballasting and tamping were followed by stabilisation and a final tamp to achieve the desired level and line. Plasser & Theurer supplied 08-16-3S (switch & crossing) and 09-16 CAT (main line) tampers, a PBR-400R ballast regulator, and DGS-90 and DGS-62 stabilisers.

Particular attention was given to final grinding of the welds, which was carried out between the second and third tamping. Weld geometry was refined to high speed standards (0·2mm in a 1m rule), improving the running surface and lessening the vertical dynamic load on the wheels.

Turnouts were delivered in two sections, the switch panel 12m long weighing 9 tonnes and the 15m crossing weighing 14 tonnes. The turnouts were pre-inspected by the project consultant and client, and moving them en-bloc avoided any loss of small components. Possession times for installing turnouts in the existing track were 5h at most. The panels were delivered on a ’just in time’ basis, lifted into place using a 50 tonne road crane or a set of gantries running on temporary track where road access was not available.

Despite the Asian economic crisis (which had a major impact on the price of imported materials), the contract was completed to budget within the original timescale.

Reader Enquiry Numbers

Ital-Thai Development Corp 121

Cogifer TF 122

Pacific Consultants International 123

Asian Engineering Consultants 124

Stedef 125

Exel 126

Plasser & Theurer 127

Thermit Australia 128

* Eric Chemineau is Trackwork Manager at the ITD/Cogifer joint venture, and Kenneth Herring is a consultant with P&A Group

CAPTION: Top: Tracklaying at Map Phra Chan

Above left: Ballasting the new third track

Right: Installation of a BS100 turnout panel by mobile crane

All photos by Eric Chemineau

CAPTION: Steel bridge at Phra Khaeo; the fastening includes a Sylomer pad between the baseplate and the steel sleeper