radius. Cars were equipped with National Steel Castings Co. "Sharon" 1/2 size MCB Couplers, and were of all steel and iron construction. The tunnel bought hundreds of Bettendorf flat cars that could be converted to gondolas and had a capacity of or . Bettendorf's patents include several pertaining to cars that match this description. Ash and excavation debris removal cars were equipped with the Newman patent dump box with a capacity. Newman, who was in charge of excavation spoil removal during the early phase of construction, developed this dump box because the clay removed during tunnel excavation was so sticky that it was difficult to dump from conventional side-dump cars. Additional cars were built by Kilbourne & Jacobs. These were simple metal flat cars wide by long with closely spaced stake pockets to restrain the cargo. Operation Revenue service in the tunnels officially began on August 15, 1906, with a 16-minute run. By that time, of track were in place, with connections to four railroads and 40 on-line customers. A total of 67 locomotives and 400 freight cars were on hand. In fact, coal delivery by subway began on October 13, 1905, when several carloads of coal were delivered from the Chicago and Alton Railroad coal chutes. In 1915, most tunnel operation occurred between 7 am and 5 pm, with limited night operation primarily serving excavation spoil removal and coal and ash service. In a typical 10-hour work day, there were 500 to 600 train movements, all conducted under the authority of a telephone-based dispatching system. Dial telephones were installed at every street intersection so that engineers could easily remain in contact with the dispatcher. In 1914, the tunnel employed 568 people, including 116 motormen, 57 elevator men, 59 truckers, 74 clerks and three dispatchers. A 1916 survey showed that the tunnel carried 18 percent of the freight traffic in the Chicago loop. In 1929, it was estimated that the tunnels handled between 200 and 300 train movements a day, with 10 to 15 cars per train. At the time, the tunnel had 150 locomotives, 2,693 merchandise cars, 151 coal cars and 400 excavation and ash cars. In 1954, the tunnel was carrying 500 carloads of freight and 400 carloads of cinders and debris daily. There were 83 locomotives, 1,609 freight cars, 55 trucks and 272 semi trailers on hand. Surface trucking was an important part of the business, required