The Northeast Frontier Railway (NFR) had placed ‘boulder wagons’ strategically near 32 vulnerable stretches ahead of monsoon.Officials said 184 wagon loads of boulders, or ‘on-wheel’ boulder reserves, had been kept ready to be rolled out at the slightest hint of danger such as abnormal rise of water level and breaches under the tracks.In addition, 80,000 cubic metres of boulders had also beeb stocked at approaches of major rivers and at locations that were traditionally known for being vulnerable. About 5,000 pre-fabricated had also kept handy for erecting temporary supports in water for bridging gaps caused by washouts.Apart from eight north-eastern states, NFR serviced parts of Bihar and West Bengal. Much of the zone, with tracks criss-crossing many rivers, was flood-prone.Sections not known to be vulnerable to floods had been affected too. Two breaches near Telta and Sudhani stations (between Kishanganj in Bihar and Malda in West Bengal) on August 13 hadt cut off railway link to the North east for almost a month in 2017.Lessons from Bihar floods“The damage caused by Bihar floods was unexpected. We have learnt to be prepared for the worst this time, at least in stretches we know that are prone to flood-induced track damage,” a senior officer of NFR’s construction wing said.Boulders, NFR officials said, were generally the first line of defence when flood waters hit a railway embankment or caused abnormal scour around bridge pillars.“Of 32 locations under NFR designated as vulnerable, 14 are in Lumding Division, nine in Rangiya, eight in Tinsukia (all in Assam) and one in Alipurduar, West Bengal. These sites are being monitored 24×7 for any signs of distress,” Pranav Jyoti Sharma, NFR Spokesperson, said.Watchmen posted on these vulnerable sections were armed with walkie-talkie sets and high-power torches besides GPS sets for better real-time planning and quick response.“The railway has also stock piled 271 rolled steel joists for construction of temporary bridges for quick restoration of track connectivity during breaches,” Mr. Sharma said.