Sophie Klimasmith was walk over the Clark Road bridge to hike in the Habitat when around 8:25 a.m. she saw a commuter rail train leaving Belmont Station.
Then, as she was heading up Snake Hill Road, "I heard this awful noise; a loud screeching," said Klimasmith, recreating the sound of steel-on-steel.
"I thought it was applying its brakes because of the Waverley stop is just up the way but it just sounded too close," she said.
It was only later did Klimasmith realize she heard the 8:12 a.m. train out of Boston's North Station to South Acton derail after leaving the Belmont Station, coming to a stop just under the bridge that connects Pleasant Street with Clark Street.
According to MBTA Police Deputy Chief Robert Lenehan while engineering, mechanical and criminal investigations are taking place, the initial examination by rail personnel is that an axle on a commuter car malfunctioned.
"Apparently, the front set of wheels just behind the engine became twisted and came up and off the rail and the engine dragged the cars for about a quarter mile," he said.
Lenehan said commuter rail trains going off the tracks is a rare occurrance happening about a dozen times in the past quarter century.
It was fortunate that the malfunction took place as the train was just exiting the station as it was moving slowly, said Lenehan.
"This was potentially very dangerous so it was lucky it was coming out of a station stop," he said.
No one was injured in the derailment and the 30 passengers were placed on MBTA buses for the remainder of the trip.
Despite the accident, Lenehan said that rail service will not interrupted as trains will use the single open track adjacent to the disabled cars.
The damaged car will be placed back on the rails with the help of a large industrial crane sometime before noon while the engine will proceed to Fitchburg. The cars will be brought back to North Station where the damaged parts will be examined.
Lenehan said all trains are scheduled to be running on time for the afternoon commute.
For neighbors and other residents, the pedestrian bridge over the trains provided prime viewing of the train and an opportunity to see the engine and cars up close.
"It's stopped," said David Klimasmith, the much younger brother of Sophie, watching what was happening from the bridge.
"I was going to tell him about seeing the train this morning," said Sophie.