GMRT scientists worried after ministry’s approval for Pune-Nashik high-speed rail

The Ministry of Railways gave ‘in-principle’ approval to the project, being executed by Maharail, on February 5. If the project is implemented, the rail route would cut through the GMRT array of 30 parabolic antennas installed in a ‘Y’ fashion across 30 km in a radio-quiet region in Pune district’s Narayangaon area.

The GMRT site is situated off the Pune-Nashik highway and was painstakingly chosen by an eminent jury of scientists, including late Govind Swarup, in the early 1980s for posing minimal man-made noise and found suitable for being favourable for long-term operations of a sensitive radio observatory.

After full-scale telescope operations commenced in 2000, GMRT has made a number of path-breaking discoveries and continues to remain a unique global facility. Since 2019, when the major upgrade (and now known as upgraded GMRT), it has achieved higher sensitivity and possesses a capability to peer deeper into the unexplored areas of our Universe. For instance, the improved computational capacity is now capable to perform data transfer at a speed of up to 40 GB/sec, allowing the uGMRT to produce useful scientific data to the tune of several Terabytes/day, which is utilised by astronomers from all over the world.

The ‘in-principle’ approval, given during a meeting held in New Delhi between Railway Minister Ashwini Vaishnaw and the Maharashtra delegation led by Deputy Chief Minister Devendra Fadnavis, came as a ‘big surprise’ to GMRT officials.

Though the Maharashtra government has been in consultation with the Centre since 2017-18 for this project, its progress has remained slow. As per the current proposal, the high-speed railway line will cover a distance of 235 km in under two hours. The proposal, prepared by the Maharashtra Railway Infrastructure Development Corporation (MRIDC), states that the train will run at a speed of 200 km/hr and stop at a total of 24 stations — eight major and 16 small ones — passing through the three districts of Pune, Ahmednagar and Nashik.

“Though there have been discussions with officials of MRIDC since early last year when we approached them with our problems from the proposed line, a resolution has not been found yet. Being a world-class observatory, we are worried about the radio noise and interference that are expected from this rail project. We are not against this project and believe in co-existence. However, our concerns and scientific interests, too, should be factored in,” a senior official from GMRT told The Indian Express.

According to the proposed rail route, a majority of the dish antennas of GMRT come within unacceptably close range of the railway line, some as close as one kilometre, the officials from GMRT said.

“The Narayangaon railway station will also be located very close to some of the antennas of GMRT. The radio noise from the moving electric train, as well as the signalling equipment which will be used for communications purposes, will be a major threat to the quality of data from GMRT. For some distance, the route even runs parallel to the existing antennas, which is unacceptable,” an official pointed out.

GMRT is a project of the Department of Atomic Energy (DAE), operating under the Tata Institute of Fundamental Research (TIFR). GMRT is a unique facility functioning within the frequency bandwidth of 100 Mhz-1,500 MHz. Built and operated by TIFR’s National Centre for Radio Astrophysics (NCRA), Pune, it is a highly sought-after telescope both within India and by scientists from over 30-plus countries. As such, the GMRT enjoys special protection for carrying out its sensitive observations in the above frequency range, for its astronomical pursuits.

To understand the problem better, NCRA officials have carried out their own studies on the implications of the high-speed railway line on the telescope’s operations.

“Our team undertook the study to measure the electromagnetic noise and interference produced by existing electric train operations at select locations in the country. Given that this is a high-speed train, these interferences would be more significant when in close vicinity. Further, we studied the frequency ranges in which the communications equipment required for the smooth operations of the high-speed trains would operate. Based on these results, we propose that such a railway line should be located at least 15 to 20 km away from any GMRT antenna,” an NCRA official said.

“We are hence worried with the present configuration of the proposed line, as it passes much closer to the antennas, and we are not sure if our concerns are being addressed. We have conveyed this to the authorities concerned in the relevant ministries, but as of now, the matter has remained unaddressed,” another scientist said.

Though the NCRA team is deeply concerned, they continue to remain hopeful of an appropriate resolution.

What could emerge as a silver lining for GMRT is a revision of the Detailed Project Report (DPR) as some technical errors were pointed out by the Ministry of Railways, as admitted by Fadnavis. Thereafter, the rectified DPR will be sent for the Cabinet’s final approval, he had announced.

When contacted, a top official from MRIDC said, “The project is still in the approval stage. However, concerns raised by GMRT officials will be resolved during our discussions in coming days. Certain precautions need to be taken for GMRT, for which detailed discussions with will take place during the meeting.”

This is an important and necessary project to address the growing traffic on Pune-Nashik route. This high-speed railway will connect the two important cities of Maharashtra and economically benefit both Pune and Nashik. In the coming days, the technical errors will be rectified and the revised DPR will be sent for Cabinet approval, Fadnavis had said on Sunday.

(Anjali Marar is the Science Communication and Outreach Manager at the Raman Research Institute, Bengaluru)