DENVER (KDVR) — Union Station in downtown Denver is one of the busiest hubs in the U.S. with tracks accommodating commuter, light rail and Amtrak trains.

The popular Winter Park Express, referred to as the “ski train,” is drawing some complaints from neighbors who say it should not idle during times when it is out of service.

Dr. Sarah Sasse, a nearby resident, told FOX31 that she expects noise to disseminate from Union Station, but what she is more worried about is the diesel fumes emitting from the train.

“The engine’s running constantly, a low humming sound, then roughly every two minutes we hear the hydraulics,” Sasse said.

According to Sasse, the noise makes it difficult to sleep throughout the night and fumes interrupt activities like eating outside.  She is concerned about the fumes and the health risks they pose to humans and pets that live and commute through the area.

The train runs each Friday, Saturday and Sunday during ski season, providing an alternative for those tired of sitting in heavy traffic along Interstate 70.

Sasse supports the use of the train, an option that limits the carbon footprint’s impact on the environment through the reduction of traffic.

“We don’t want the ski train to necessarily go away or end,” she said, “but if the train is not in use during the week we don’t understand why it needs to be on.”

Amtrak responds

The FOX31 Problem Solvers asked Amtrak about the train’s idling schedule. A company spokesperson explained that the diesel engines power the systems in the train, including heat, which must be powered on to protect the water systems.

According to their response, “[They] have moved the train as far as possible from the condo buildings, but diesel fuel also can gel in cold temperatures. So the engines must idle. This is regardless of whether the engines are used for the Winter Park express or for another service.”

The Denver Department of Public Health and Environment told FOX31 that if noise is coming from idling trains, the city does not have the authority to take action. The noise and fumes are regulated under federal code and enforced by the Federal Railroad Administration.

Dr. Anthony Gerber of National Jewish Health told FOX31 that diesel fumes contain dangerous particulates.

“If residents are smelling it, you can imagine that there is a high enough concentration that it can bother sensitive people,” he said. Gerber added that some conditions, like asthma, can be triggered by fumes. Anyone experiencing severe symptoms should consult their physician.

The train will continue service to Winter Park through April Fools’ Day