Taking advantage of the drastically reduced traffic due to the lockdown, South Central Railway recently took up comprehensive track maintenance work for the iconic three kilometre long Rail-cum-Road Bridge over the river Godavari near Rajahmundry in Andhra Pradesh.
This level of maintenance work was conducted for the first time after commissioning of the bridge in 1977. In order to complete work unhindered, a 36-hour traffic block was taken.
The dual deck bridge has a road on the upper deck and the railway line on the lower deck. It is a vital connection on the Vijayawada-Visakhapatnam trunk route, part of the Golden Quadrilateral route of Kolkata-Chennai.
Track renewal work was conducted, with the replacement of rails and sleepers on the six spans with pre-stressed concrete deck slabs.
Deep screening of ballast was done.
The mechanised process required minimal physical labour, and was carried out with the modern PQRS (Plasser Quick Relating System) cranes.
The work presented challenges on technical aspects associated with the engineering of the bridge, which handles rail traffic on the lower deck and road traffic on the upper deck.
All 6 spans of deck slabs (beam-like support between 2 piers on either side) are on a sensitive 6-degree curve, making it tough to handle maintenance tasks within limited time.
Working space on the bridge for the rail personnel involved in the job was insufficient, requiring them to make adjustments and accommodate co-workers in completing the task. Yet another obstacle to overcome was the lack of required space to provide for the auxiliary track. The track enables movement of PQRS cranes for undertaking the work.
The problem concerning lack of space for storing 8,000 ballast (stone) bags required for the work, was overcome by setting up a separate iron plate type platform to hold the bags before being utilised to fill the underbelly of the track and sleeper.
At first, the existing track length was removed using the PQRS machines. Later, the entire slab was swept to check for any cracks. The low height brick walls, constructed at the ends of the slabs on both sides for curing during casting of these slabs, were removed so as to increase the efficiency of the drainage system.
The slab strength was also ensured by a physical check using the rebound hammer. Simultaneously, a 180-meter length of approach to the bridge was also deep screened by using JCB excavator.
Gajanan Mallya, General Manager, South Central Railway, who keenly monitored the bridge maintenance work, was highly appreciative of the team of Railway engineers and workforce of Vijayawada Division which carried out the task successfully.
More about the Godavari Bridge at Rajahmundry
The Rail-cum-Road Bridge with 34 spans (28 spans with steel girder and 6 spans with PSC deck slabs) across River Godavari is the 3rd longest Rail-cum-Road structure in India, next only to the Digha-Sonpur bridge across River Ganges near Patna and Bogibeel Bridge across River Brahmaputra in Assam.
Built by the Braithwaite, Burn & Jessop Construction Company, the Rail-cum-Road Bridge streamlined train movement on the vital Chennai-Vijayawada-Visakhapatnam-Howrah sector, which was earlier catered by the 1st Godavari bridge, more popularly known as the Sir Havelock Bridge, now a heritage structure.
Another bridge which added to the chain later is the pre-stressed concrete Bow String Arch shaped 3rd bridge across River Godavari at Rajahmundry.