The River LINE is the first modern Diesel Multiple Unit (Interurban, Tram-Train although it’s not electric so it doesn’t fully fit this definition) train to open in the United States. The 34-mile-long line opened on March 14, 2004 at its current length from the Trenton Transit Center to the Camden Waterfront. It has never been extended although one new infill station, Pennsauken Transit Center opened in 2013.
It is classified by New Jersey Transit as one of its Light Rail Lines but operates using diesel (not overhead electric lines). It operates much closer to a what would be a historical diesel railroad branch line except for the street running sections through Downtown Camden just like historical United States Interurban Lines (although these were generally electrified). The rolling stock is European DMU technology, specifically Stadler GTW articulated rail car technology with either one or two articulated car trains operating along the line.
The corridor is shared with regular freight trains, although US FRA train crash test standards from the time the line was built require time-based separation with freight trains using the corridor at night and the River LINE DMUs during the day. This time-based separation continues to this day requiring service along the majority of the corridor not allowed to begin until just before 6:00am and ending by 10:00pm Sunday night through Friday night. Operations are permitted through the night on Saturday nights when the last trains leave Trenton or Camden just before Midnight. A few trains begin just before or after this curfew along sections of track, particularly at the Southern end of the line south of that are exclusive to passenger trains from Pennsauken south to Camden (late night service until Midnight operated on this portion of the line from 2005 to 2010).
The line is designed for 15-minute service and is largely single-tracked with passing sidings and significant portions of double-tracking. Weekday peak hour service should operate every 15 minutes, with base half-hourly service the rest of the day on weekdays and on Saturday and Sundays. In August 2024, due to a huge number of broken down DMUs creating lots of missed trips, service was reduced to every half-hour seven days a week because of a lack of spare rolling stock. Diesel rolling stock generally ages much faster than fully electric trains due to all the various extra parts required for a diesel engine (EMU railcars generally are designed to last 30 to 40 years, with buses only 8 to 12 years).
The stations are all relatively simple with a unique platform height for North America of 23 inches. This height is closer to what is standard in Europe and allows for level boarding with the Stadler DMU Cars. The stations all have a standard design with cream-colored columns holding up a gabled roof canopy structure over a small portion of the middle of the platform. This is where the stations TVMs are generally located, for the lines Proof-of-Payment fares with fare inspectors carrying out random fare checks. Most tickets need to be validated at a time stamp next to the TVM.
Artwork at stations is also unified through the NJ Transit's Transit Arts program. All is part of River Rail Revival by Katherine Hackl, Hiroshi Murata, Marilyn Keating with similar elements at all RiverLINE stations, including decorative tiles along the platform canopies, railings, and other sculptures.
The RiverLINE is one of the more controversial late 1990s-early 2000s rail projects in the nation. The line basically exists because South Jersey politicians wanted a piece of the rail building pie that was building large projects in North Jersey like the Hudson Bergin Light Rail, the modernization of the Newark City Subway into the Newark Light Rail, and the Secaucus Junction Rail Station unifying all of New Jerseys rail lines, except the Atlantic City Line. In order to construct the new line, the line was built entirely through local not Federal funds, primarily via the State Transportation Trust Fund. h New Jersey Transit didn't even apply for Federal Funding compared to all of the North Jersey projects being built with lots of Federal Funds. This was done because planners and politicians knew that the Federal cost-benefit ratios to provide Federal Funding to projects would make the River Line dead upon arrival.
When the line first opened projected ridership was so low that some thought the line should operated fare-free because the cost to collect fares (maintaining the TVMs and provide fare enforcement officers) would more expensive than the meager amount of revenue the line would bring in. The line opened with a 7% cost-recovery ratio, although ridership for the line has exceeded expectations. In 2019, it cost an average of $14 to provide each trip on the railroad, which isn't bad for such a unique operation. The low cost- recovery ratio for the River LINE is because there is just a flat fare, the same as a single-zone bus ride and not the distance-based fares of all NJT buses and rail lines with complicated fare zones. The fare was only $1.15 when the line opened in 2004 and rising to only $1.80 today. If the River LINE were a bus route it would cross through 6 to 7 fare zones — NJ Transit's bus fare zones are super complicated — with a ride costing between $4.85 and $5.50 one-way as of July 2024.
An interesting tidbit about the River LINE is although its just 20 years old (as of 2024), it has gone through three different types of Ticket Vending Machines. The first two only issued same unvalidated purple tickets that then must be stamped in the validator next to them. In 2023, in addition to the newest TVMs accepting contactless payments, new digital validators were added that also allow a passenger to simply tap their credit card on a validator and show the credit card to the fare enforcement officer for Proof of Payment.