Work on metro rail to begin after BMRTL acquires land

Work on metro rail to begin after BMRTL acquires land

The Hindu

May commence operations by 2008 if work goes on as scheduled

BANGALORE: If work on the Metro Rail project starts as scheduled by the end of this month, it can probably transport the passenger by early 2008 and reach full capacity two years later, if controversy does not hold it up further.

The time lag will be due to technical reasons. Complicated engineering technology will be used to lay foundation caps and columns for girders on which the railway line is eventually to be built.

Engineers of the Bangalore Mass Rapid Transit Rail Ltd (BMRTL) say each supporting girder will take seven days to be erected.

The process will start after the BMRTL acquires 3.5 metres of space on either side from the centre of the road over which the railway line is to pass. The process will be different in the underground stretches. Once the space has been barricaded, a "bored cast in pile" will be constructed, which will act as a foundation for the girders.

Four 15-metre deepholes will be drilled and filled with reinforced steel and concrete. These will act as four legs for the slab above, called the pile cap. This is to the rail system quake-proof. The next stage will be setting up the pile cap, which will be below road level by about five metres. The cap will then be ready to take the load of the girder columns. The entire process will take at least seven days, the engineers estimate.

The supporting columns for the metro will be done in two km stretches and traffic may have to be diverted on those stretches for about eight weeks. There will be 18 columns each of two km and this means only about 7 metres of the road will be closed at a time. Part of the work is planned to be carried out during nights to avoid disturbance.

Each of these columns will be 1.5 metres wide and 5.5 metres when laid in place and will be transported from the places where they are cast to the site at night.

The engineers say the real challenge will be in connecting the girders together. This work may last two nights. From each girder, eight more have to be linked to reach the next column; each girder is 9.8 metres wide. An epoxy material will be used to bind the columns together. Once all 36 km of girders are in place, the process of laying the rails starts.

The approximate time frame is for each 2 km stretch to be completed in about three months, the engineers say.