Alastair Jamieson / NBC News
A sign at Stratford train station, at the Olympic Park in East London, warns travelers of the suspension of Central Line trains.
Updated at 5:39 a.m. ET: LONDON -- Olympic spectators traveling to the Games in London faced delays Tuesday after a faulty train temporarily forced the closure of one of the busiest underground links to the Olympic Park.
There have been concerns over whether London's public transport system, the busiest in Europe, would be able to handle the rush of spectators attending the Games.
The system appeared to cope well with the crowds on Monday.
A smoke alert halts subway service on London's Central Line which transports thousands of spectators to the tube stop at Olympic Park. NBCNews.com's Dara Brown reports.
Operator Transport for London told NBC News in a statement that the Central Line service, which stretches east to west across the city, was temporarily halted east of Liverpool Street station on Tuesday after a driver reported smelling smoke.
The driver's train was taken out of service at Leyton, one stop to the east of the Stratford station which is being used as the hub for people arriving at the Olympic Park.
Although Transport for London told NBC that Central Line services resumed within hours, the line continued to suffer delays. Staff advised Olympic fans to travel to the park via a number of other rail routes, Transport for London said in a statement.
British Transport Police said the problem may have been due to smoke coming from the train's brakes.
London's entire transit network handles an average of 12 million trips a day.
NBC News staff, Reuters and The Associated Press contributed to this report.
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