The rail viaduct holds six tracks, which are numbered 1, 2, 2a, 4, 6, and 8 from north to south. Tracks 1 and 2 are primarily used by CSX Transportation for freight service on their Berkshire Subdivision and are served by platforms A and B - track 2 is also used for boarding and disembarking of the daily Lake Shore Limited train. Track 2a, which connects with both the New Haven-Springfield Line and the CSX tracks, is owned by Amtrak is used mainly for storing train equipment and is not normally used for boarding. Tracks 4 through 8 (serving platforms C and D) are currently used for most Amtrak service; they connect directly to the New Haven–Springfield Line west of the station, but only connect to the CSX tracks east of the station. (The "Lake Shore Limited" uses the CSX tracks for this reason.) West of the station, the New Haven–Springfield Line curves to the south while the Berkshire Subdivision continues on to cross the Connecticut River on a twin truss bridge. The Connecticut River Line connects to both lines west of the station, although it requires a backup move to reach tracks 4 though 8.