Mass-spring system to reduce vibrations in Metro trains

The Delhi Metro has decided to use mass-spring system in the upcoming underground stretch between Central Secretariat and Kashmere Gate to reduce vibrations generated due to train movements and to protect the buildings at the surface, which includes some of the heritage structures.

The mass-spring system, which uses soft steel coil springs in the concrete track slabs, helps in reducing vibrations and noise due to movemnets of train.

The upcoming stretch of metro project phase-3 will pass under heavily populated old and central Delhi which is home to several heritage projects. The system would erase all fears of danger to the buildings on the surface due to vibrations underneath, DMRC officials said. 
 
A layer of material is laid below the track which absorbs vibration caused by the movement of train on to the surface of the tunnel. “Since the vibrations do not affect the tunnel surface, the structures in the area above are not affected,” said Kumar Keshav, Director (projects), DMRC. 

Vibrations caused due to movement of trains had been a matter of controversy in the past.

Over a thousand residents of the Shahbad Mohammadpur village located in
south- west Delhi claim that immense vibrations caused due to the high speed of the trains on Airport Metro line are responsible for causing cracks in their house. The DMRC has taken a serious view on the matter and has ordered a detailed report on the issue.

Work starts for Phase III

The Delhi Metro launched the process of boring tunnels for construction of a three-km underground corridor aimed at decongesting the busy Rajiv Chowk station under Phase-III project.

The Tunnel Boring Machine that has been brought from German company Herrenknecht and assembled in Chennai was lowered on Tuesday near Chemlsford Club in central Delhi.

“It is an important event of the Phase-III. I congratulate the entire team for this job. We will be using more than 20 TBMs in Phase-III which is a very safe method,” DMRC Managing Director Mangu Singh told reporters at the site.

The 924-metres long tunnelling work from Central Secratariat station to Janpath will be completed by June 2012.

The second TBM will be lowered in the first week of March. Both TBMs will work for a certain distance away from each other along the alignment.

All four-coach trains would be converted into six-coach  by June and the six-coach trains would be converted into eight-coach ones by April next year, added Mangu Singh.