Amtrak and CTrail’s Hartford Line are the successor of the New Haven-Springfield Shuttles, the name of all non-through trains (the Vermonter, and select Northeast Regional trains) on the route that were entirely operated by Amtrak until June 16, 2018. Today weekday service consists of 4 Amtrak shuttle trains, consisting of a P42 Locomotive, an Amfleet I coach, and an Ex-Metroliner cab car for push-pull operations, and 6 (3 trains operate only between New Haven and Hartford) CT Rail trains using generally leased ex-Boston MBTA MBB Coaches, and second hand GP40-3H locomotives that were overhauled and previously used on Shore Line East. As part of the start of preparation for Commuter Rail service the stops in Wallingford, Meriden, and Berlin were relocated or rebuilt and now have high-level platforms (all Hartford Line content is from 2013 to 2014, before these stations were renovated) so content at these stations shows the old station configurations and locations. The project also restored the second track to the Hartford Line, that Amtrak eliminated in 1990 when service was reduced to four daily shuttle round-trips (plus some through trips) to reduce maintenance costs. Commuter service is supplemented by one daily Northeast Regional train (plus a second northbound one on Saturday nights, and southbound on Sunday mornings) that is a through train from Washington (Roanoke for one Sunday train) to Springfield. The Vermonter also serves the corridor, but CTrail unreserved cheaper commuter fares are not valid on this service.

The Hartford Line has seen continuous Amtrak service since Amtrak began in 1971, with Shuttle train service running pretty much like it does today, as low as 4 daily round-trips. The line originally used Budd RDC cars. In 1980 the state of Connecticut purchasing SPV-2000 units – that were an unsuccessful, poorly powered DMU successor to the Budd RDC – and service was increased to 12 daily roundtrips, although this was reduced to 6 round-trips in 1981 after ridership failed to increase. After the unreliability of the SPV-2000 cards, in 1986 Amtrak began using Amfleet cars and diesel locomotives on the line; along with through-run service on regular Northeast Corridor trains to and from Boston, with shuttle trains consisting of adding or dropping cars during the engine change in New Haven.

In the late 1990s, today’s current Shuttle train format took shape with the through-car service discontinued, and trains beginning to run the same configuration as today with one P42 locomotive, an Amfleet I Coach and an ex-Metroliner cab car on the service. The cab-car eliminates the need to wye trains after the short 90 minute round-trip allowing push-pull operation. This service change supplemented the elimination of engine changes in New Haven on trains to and from Boston between 2000 and 2002, after electrification was completed. Service was reduced with Busitution between 2015 and 2017 to allow the infrastructure upgrades for CTrail service to take place.