To address overcrowding, in 1909, the New York Public Service Commission proposed lengthening platforms at stations along the original IRT subway. As part of a modification to the IRT's construction contracts, made on January 18, 1910, the company was to lengthen station platforms to accommodate ten-car express and six-car local trains. In addition to $1.5 million (equivalent to $ million in ) spent on platform lengthening, $500,000 () was spent on building additional entrances and exits. It was anticipated that these improvements would increase capacity by 25 percent. At the 72nd Street station, the northbound platform was extended south and north, while the southbound platform was extended south and north. A new crossover and signal tower were also built in conjunction with these extensions. Work progressed on the platform extensions at 72nd Street during 1910 and 1911. On January 23, 1911, ten-car express trains began running on the Lenox Avenue Line, and the following day, ten-car express trains were inaugurated on the West Side Line.