Nearest road 10 km away, Central Railway's upgrade of 'inaccessible' ghat bridge begins

Mumbai: Pune-Mumbai train services , which have been affected owing to damage in the ghat section during monsoon, are likely to be fully restored by January-end, with the Central Railway upgrading a 150-metre-long bridge in a treacherous and inaccessible spot near Monkey Hill , Khandala .

A 30-meter approach section of the bridge between Monkey Hill and Nagnath station, on Pune-Mumbai line, had sunk during massive rain and services on this stretch have been suspended since October 3.

The other two lines—Mumbai-Pune and the middle one—are operational.

CR had the option of a temporary solution of allowing trains through speed restrictions, but there were fears that the embankment may sink further —the soil is prone to sink and it is difficult to even station JCBs and excavators.

So, CR is working to increase the length of the bridge over the embankment by adding two more spans (pillars) at a cost of around Rs 10 crore. CR’s chief public relations officer Shivaji Sutar said, “We want to ensure that the line does not sink in future even if it rains as heavily as this season.”

Senior divisional engineer (construction) RK Yadav said, “The main challenge here is the inaccessible terrain. The road is around 10 km away. So transporting material, including concrete, stones and even machinery was a huge challenge.” All material including concrete, boulders and even JCB as well as excavators had to be brought by train from Lonavla.

Around 50 workers are deployed to carry out work in three shifts.

Additional divisional railway manager Ashutosh Gupta said, “We had to first build a 25 mtr gabion wall on the hill edge to prevent slipping of soil. Thereafter, we began micro-piling work by digging 2-3 metres into the hard rock base.” Around 580 micro-piles will be used of which 480 have been done.

After micro-piling, concrete is poured before launching the girder and then tracks will be laid over it. However as the concrete takes around 1 hour to each the site, a chemical material called retarder is mixed to delay solidifying of the concrete.

Yadav said, “This type of bridge extension has been undertaken at many places, including Konkan Railway, but nowhere they had to face such a challenge that is posed by the inhospitable condition in Monkey Hill.”

Around 350 truckloads of boulders and 100 trucks of quarry dust will be moved by train by the time the work is complete. Sutar said, “The corridor will be fully restored by mid-January.”