Although the route east of New Haven is electrified under Amtrak's 60 Hz traction power system, Shore Line East currently operates entirely with diesel locomotives. Once the full order of M8 railcars are in service, and Amtrak tests and approves the M8s for usage east of New Haven, ConnDOT plans to use 24 to 32 cars for electric SLE service to reduce diesel emissions. The diesel trainsets will be moved to service on the Danbury or Waterbury branches, or to the Hartford Line from New Haven to Springfield.