Construction was started in May of 1892. However, soon after the start of construction, there were many complications. The project was difficult due to complex geological formations beneath the river, and there were frequent blowouts and floods. It was curtailed for a little while when five people were killed on December 28, 1892. Work was stopped in 1893 as a result, and it was boarded up. Until Steinway died, some attempts were occasionally made to resume construction.
The project was revived in 1902 with financial support from August Belmont, Jr., who assumed the cost of building the Interborough Rapid Transit Company (IRT) and its plan of equipping and operating the first subway. Surveys and tunnel plans were prepared from scratch by the IRT. It was completed in 1907, after the city had objected to it multiple times. Some demonstration trolley car runs were conducted through the tunnels in 1907; however Belmont did not have a franchise to operate a transit line. The tunnels, with trolley loops on both the Manhattan and Queens sides, remained idle until Belmont sold them to the city in 1913.
The original IRT plan was to resume trolley car operation, but this was rejected in favor of a regular rapid transit train service. The tunnels were measured, and it was found that only minor modifications were needed to allow for third rail installation. The loops and the ramp were unusable by regular subway cars due to the tight 50' radius of the loops and the steep 6% incline. However, the roadbed did not have to be lowered, nor was special low profile rail required, but the duct banks in the tunnels were replaced. The tunnels were modified to accommodate IRT subway cars in 1914. The first IRT Steinway test train between Grand Central and Vernon Avenue (today's Vernon Boulevard – Jackson Avenue station) ran June 13, 1915, with regularly scheduled service beginning June 22.
When Belmont modified the IRT Flushing Line to extend to Times Square and to Flushing, the loops on the Queens side of the tunnel were obliterated in the wake of new construction. The loop on the Manhattan side, however, is intact and currently occupied by maintenance rooms.