The Hyderabad Metro Rail has said that its rail overbridge (ROB) over the railway lines at Begumpet and the adjacent railway station was successfully completed, closing a critical gap in corridor III of the project.
With this and completion of the Oliphenta bridge near Secunderabad railway station (expected to be done in a few weeks), the extension of the eight km stretch of the Nagole – Mettuguda metro line up to Begumpet has become feasible.
The construction of the bridge was taken up under highly challenging conditions given the railway lines and the station below were busy round the clock, a release of HMR said.
The total length of ROB was 450 ft. It was a curve, wedged between Begumpet flyover on one side and several buildings on the other. A special method called “bridge builder” was used in the construction in view of the curved nature of ROB, for a height of 60 ft from a narrow road and railway lines below.
HMR managing director N.V.S. Reddy said in the release that erection and movement of the bridge builder device, weighing 100 metric tonnes, was an engineering nightmare.
Pre-cast segments of the builder were lifted with heavy duty cranes, taking all safety precautions and not causing traffic disruption.
To meet multiple technical challenges, the bridge builder was specially built and load test performed at the Uppal casting yard before it was brought to Begumpet and mounted on the already built metro viaduct from Varun Motors and Country Club sides.
The whole metro ROB was built in three parts with the main portion (span) coming up over railway lines and the railway station.
The two ends were 130 ft and 107 ft respectively. After erecting the bridge builder on both sides, it was anchored safely with counter weights.
The Indian Railways gave only ‘three hour blocks’ for launching each segment by stopping trains beyond midnight once a week.
Grasping the ROB
Length of ROB 450 ft
Height of ROB 60 ft
Length of the central span 213 ft (over railway tracks)
Length of end spans 130 ft and 107 ft
Weight of each segment 54 tonnes
Length of bridge builder 130 ft
Width of bridge builder