Federal regulators and passenger railways are both concerned about passengers with mobility impairments that limit their abilities to use stairways. Toward that end, federal policy and railway practice strongly encourages developing services that allow for level boarding and alighting from commuter rail trains without using stairways. Beyond benefiting individuals that have trouble using stairs, level boarding can also lead to significant improvements in service delivery for the rest of the public by reducing unproductive station dwell times, improving safety and creating opportunities improve crew efficiency.
One principal obstacle to level boarding has been the concerns of freight railroads that operate over (and often own) trackage shared with the passenger trains. The freight operators wish to maintain a full horizontal clearance envelope allowing unrestricted operations. These concerns often limit the close door/platform interface necessary for level boarding.
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