MUMBAI, Jan. 6 -- Indian Railways is set to conduct trial runs of an 18-coach suburban train for the first time, with the Western Railway (WR) preparing to test the longer rake on the Virar-Dahanu corridor on January 14 and 15. The trials will assess critical safety and performance parameters, including Emergency Braking Distance (EBD) and coupler forces, for 18-car train formations fitted with three-phase propulsion systems. According to the central railway ministry's communication, rakes manufactured by Bombardier will be tested at speeds of up to 110 kmph, while those produced by Medha Electrics will undergo tests at a maximum speed of 105 kmph. Sources said the coaches will be suitably upgraded to meet requirements for speed, stability and oscillation trials before testing begins. Railway officials clarified that the exercise is purely experimental and does not signal the immediate introduction of 18-coach local services in Mumbai. "These are mandated technical trials. The final configuration of the coaches is still being worked out and there is no decision yet on operating 18-car locals," a senior WR official said. In September last year, HT was the first to report that the plan to explore longer suburban train formations was proposed to the state government as part of future phases of the Mumbai Urban Transport Project (MUTP). Under the proposal, the railway authorities plan to procure 2,856 coaches at an estimated cost of Rs.21,000 crore. These are primarily intended to form 238 air-conditioned (AC) local trains with 12 coaches each, with provisions to expand the formations to 15 or 18 coaches once infrastructure upgrades are in place. Such upgrades would include extensions to platforms, modernisation of signalling systems and strengthening of track infrastructure. The procurement of 238 AC local trains is partially financed by multilateral development banks. Officials said the tendering processitself could take six to eight months, while the induction of the first such AC local train could take six to seven years....