How Delhi Metro overcame space crunch

NEW DELHI: Located in one of the congested areas in Delhi, the upcoming Rajouri Garden Metro station in phase III—which will be perpendicular to the existing Blue line (Dwarka sector 21 to Noida/Vaishali), will be unique in many ways.

It will be the first station to be connected to another as an interchange station through a travelator. It is being built using a technology that will literally "push" a 300-tonne, 60m-long span or part of the viaduct, across pillars. Most interestingly, the viaduct or alignment passes through a space that has just enough area for the construction to come up—11m to be precise—between the Raja Garden flyover and commercial establishments for a 200m stretch.

Another interesting aspect is that a part of the Rajouri Garden station of line 7 ( Majlis Park to Shiv Vihar) will be hanging over the road—with access being possible only through a foot overbridge. Said a DMRC official, "Due to space constraints, the concourse of the station will allow access to only one platform. To enter the other platform, commuters will have to take a foot overbridge from the concourse to the platform."

Space constraints, in fact, have marked the construction of the alignment in this station. The viaduct coming from Mayapuri is wedged between the Raja Garden flyover and a 200m stretch of buildings that house shops that couldn't be demolished. This space is 11m—just enough for the viaduct to come up. Further ahead, the location of the Raja Garden flyover and the existing line 3 corridor would mean that the new corridor would have to go under the old Metro line, and beside the flyover. The viaduct now will be built between two pillars or piers of the line 3.

What makes the construction interesting is the fact that a 300-tonne, 60m-long steel span—a slab of the viaduct—will be taken up to the top of the pillar and "pushed" on to the exact location over other pillars. The process of assembling the span will take 30 days, while the pushing will take 6-7 days for the span to be put in its place. Every day, only 10m of the span will be pushed. "This will be done using push-launching technology, which has only occasionally been used by Delhi Metro before," said the DMRC official.

Once the construction is over, the new station will be connected to the existing one through a travelator. "It will be one of the first stations in the Delhi Metro network to be connected in this way," the official added.

According to Delhi Metro, that wasn't the only challenge. "A huge, open drain —3.75m by 2.1m in size approximately—was running beneath the proposed Rajouri Garden station and some of the foundations were infringing in the drain. The problem was resolved by diverting the open drain stage-wise," said the Delhi Metro official.