The culprit has been identified.
The derailment of a Metro coach near Yamuna Bank station on Sunday has been blamed on the ballast that supports the track.
About four km of the Metro track from the Yamuna Bank station till the river Yamuna is on ground level and is supported by ballasts, unlike elevated and underground stretches where the track is laid on a concrete viaduct or bed.
The ballasts, that keep the track in place, are made of crushed stones.
“The wheels of the train’s second coach got derailed because the tracks were not evenly aligned. It seems there was a problem with the ballasts that support the track,” said a Delhi Metro Rail Corporation (DMRC) official on condition of anonymity fearing reprisal.
On Sunday, a metro train with 14 passengers on board derailed after starting its first journey of the day from Yamuna Bank station to Indraprastha station at 6.02 a.m.
DMRC suspended the Junior Engineer in charge of track maintenance and instituted an inquiry committee.
While most Metro tracks are ballast-less, DMRC opted for conventional ballast tracks for two stretches — near Shahdara (3 km) and Yamuna Bank (4 km), apart from all its train depots. In both these areas, the ballast track starts where the track crosses river Yamuna and enters East Delhi.
The Indian Railways uses ballast track across its nationwide rail network.
“We have used conventional ballast tracks wherever the train travels at ground level,” said Kumar Keshav, Director (Projects) of DMRC.
“Ballasts are flexible and keeps moving, which gives them a slight spring action. We carry out regular maintenance of the tracks.”
The ballast track was last compacted when the Yamuna Bank station opened in May.
“The real cause behind the incident would only come to light when the inquiry
committee submits its report,” said DMRC spokesman
“Ballasts provide resilience to the wheels but it has to kept free from waterlogging and excess sinkage. During heavy rain, ballasts may suffer
sinkage when certain stretches of the tracks may get a bit out of the line,” said a
senior Indian Railway engineer on condition of anonymity, as he is not authorised to talk to the media.