The Denver Regional Transportation District has operated the first test train on 12.1-mile West Rail Line, which will connect Golden to Denver in the US state of Colorado, according to Railway Technology.
Testing on the entire length of the line will be carried out over the next few months with power provided from overhead electrical lines.
The West Rail Line was the first project of Denver RTD's FasTracks programme to commence construction in 2009 and is scheduled to open to the public on 26 April 2013.
The line starts at the Auraria Campus in downtown Denver and runs through Lakewood ending in Golden, serving Denver, Lakewood, the Denver Federal Center, Golden and Jefferson County.
Following the initial trial run, the train will stop at all rail crossings to carry out additional tests to make sure that all at-grade crossings are functioning properly.
Each crossing is expected to take one to two days and multiple crossings will be tested per day.
The West Rail Line will connect with the existing C and E lines at Auraria West Station, offering commuting options to Downtown Denver, Lodo, Englewood, Littleton, Aurora, Greenwood Village, Centennial and Lone Tree.
FasTracks is Denver RTD's transit expansion programme to construct 122 miles of commuter rail and light rail, 18 miles of bus rapid transit service, add 21,000 new parking spaces and renovate Denver Union Station and redirect bus services to better connect the eight-county district.