Friday, February 8
The Thames tunnel was originally built below the river in London to solve traffic congestions way back in 1840. But due to a curious set of circumstances, it became part of an underground metro system dedicated to running trains and set the trend in other parts of the world.
It took nearly 15 years to excavate the tunnel which was a grand distance of 400 metres but it was unique engineering feat at that time. The construction had to be halted several times due to floods, tunnel collapses and lack of funds.
A special tunneling device called the tunneling shield made it possible for worker to dig through the soil while keeping them protected from collapses. It had a 36 cells each large enough to fit a worker who excavated a small area in front of him. Once the portion immediately in front of the workers was dug, the shield was pushed forward. Today the Delhi Metro is able to do the same distance in less than a month.
However when the tunnel was ready, carts could not use it since there were no ramps for them to enter and exit the tunnel due to a cash crunch! So it was used by pedestrians for over 20 years.
In the 1869 the tunnel was taken over by London Railway and finally it became part of the London Metropolitan Railway.