चेन्नई Chennai (MAS): In the 21st century, engineers are turning back to the 60s for a little help. Chennai Metro rail is bringing back the railway relics. Turntables – an equipment that helps to turn trains and locomotives in a different direction is going to re-surface on Chennai Metro.
Turntables are huge circular tables with tracks fixed on them. This technology was widely used at railway yards till the 1960s. Railway yards at Royapuram and Egmore had the facility.
As steam locomotives could be driven in only one direction, turntables at railway yards helped turn the locomotive in the opposite direction. With the arrival of diesel and electric locomotives that are bi-directional, turntables went out of use.
Turntables were used to turn steam locomotives in railways so that they can be switched from one direction to another. Steam locomotives could be driven on only one direction while modern diesel and electric locomotives need not be turned at a depot to connect to the next train.
This technology was widespread in railways till the 60s. It vanished from the scene after railways switched from steam to diesel locomotives that are bi-directional and can be driven forward and on the reverse with same speed and efficiency.
After several decades, now metro rail is reviving the technology. Three turntables have been set up at metro rail’s Koyambedu depot. With the help of digital technology, the turntables will help turn bogies, wheel sets and axles of metro rail trains for maintenance. The wheel sets need to be maintained periodically and are done after detaching them from coaches.
“The bogies will be pulled on to the turntable using a mini engine and then turned in the direction to which it has to be taken. Once the turntable completes the turn, the bogie will be pulled out. This mechanism will help move bogies from one section of the depot to another,” said a senior official of Chennai metro rail.
The equipment saves space, says an official, as otherwise lengthy tracks have to be laid for trains or bogies to be turned around.
A turntable for standard gauge metro rail is 3500mm in diameter. The decks sit on center pivots at the centers and castors on the peripheries for turning.
Two pairs of rails are mounted and positioned perpendicular to each other across diameter on the deck of each turntable to accommodate bogies.
These equipment are widely used in metro rail maintenance depots world over.
Apart from Chennai metro rail, turntables are also used in metro rail depots in Delhi and Mumbai.