Mumbai, May 14 -- Train managers or guards on Central Railway (CR) resorted to a "work-to-rule" agitation on Wednesday evening to protest against a new rule aimed at stopping trains from overshooting platforms. From around 5.30pm, for 15-20 minutes, guards followed arcane rules which are rarely followed now - such as limiting train speeds to 5 kilometres per hour or less while entering stations, and not giving the signal for departure if commuters were seen hanging by the foot board. Though brief, the stir during the evening rush hour had a cascading effect on suburban services. Three trains were cancelled and several services were delayed by 20-25 minutes, even as massive crowds gathered at the Chhatrapati Shivaji Maharaj Terminus (CSMT), Dadar, Ghatkopar, and Thane stations. On May 7, CR introduced a new rule requiring train managers to give an advance single bell signal to motormen around 350-400 metres prior to stations where trains are scheduled to halt. If motormen do not respond, and trains approach the platform at higher than prescribed speed, train managers must apply the emergency brakes independently, the rule says. "The rule was introduced following a recent incident where a train skipped its halt at Vikhroli," a CR official explained. Train managers, however, said they were not consulted before the rule was firmed up and a circular was issued for implementation. They also questioned the rationale behind the rule, saying it was impractical to ring a bell before every halt, as the number of stations across CR's main, harbour, and trans-harbour lines was more than 100. "Besides, if a train overshoots the platform despite the rule, will railway officials take responsibility," a train manager asked, requesting not to be identified. On Wednesday evening, crowds swelled at platforms once the 'work-to-rule' stir began. At CSMT, the 5:45pm Asangaon Fast local was fully packed but still stationary on platform number 6 at 6:15pm. A sudden announcement that the 6:06pm Ambernath local on platform 5 would depart first triggered a frantic dash among passengers to shift to the other train. At Parel, the 6:45pm Parel-Kalyan AC local was packed to capacity at the originating station itself, obstructing the automated doors from closing. Railway Protection Force (RPF) personnel tried to push passengers inside to shut the doors, but achieved little. Union leaders warned that Wednesday's brief protest was merely a warning and demanded that implementation of the circular be stayed until discussions are held with train manager representatives. CR officials said a special meeting would be convened on May 18 to deliberate on the matter....