SYSTRA used its RAILSIM software to perform a comprehensive traction power system study for the Long Island Rail Road (LIRR), which operates the busiest commuter rail network in North America. The vast majority of the LIRR’s 781 scheduled daily train movements utilize Electric Multiple Unit or dual-mode diesel/third rail mode locomotive rolling stock.  As the LIRR operation is forecast to expand by nearly 50 percent by the year 2020, the electric traction power system will continue to require reinforcement and capital investment.

As the LIRR and MTA work towards completing the 2005-2009 capital program (and initiate development of the 2010-2014 capital program), a comprehensive analysis of the additional traction power system requirements was needed. LIRR commissioned SYSTRA Engineering, Inc (SYSTRA) to perform this important study, following the successful completion of a similar study by SYSTRA for Metro-North Railroad.

SYSTRA created a detailed RAILSIM simulation model of the entire system and its electrical network. Since RAILSIM Load Flow Analyzer (LFA) has no limitation on the topology or the track mileage of the system to be modeled, the entire LIRR traction power system has been modeled as a single load flow model. This includes all 109 rectifier substations and breaker houses, all conductor rails, running rails, positive feeder cables, negative cables and negative reactors, sectionalization switches and third rail gaps. All trains in the system are simulated using RAILSIM, with appropriate track-specific power demands generated through train movement and performance calculations.

RAILSIM LFA produced detailed load cycles for all the LIRR’s traction power equipment, including:

• Rectifier load cycle
• Positive feeder load cycle
• Negative feeder load cycle
• Negative reactor load cycle

Detailed outputs and summaries for all the power equipments in the system were included in the output data, as were plots of train voltages as the trains move through the system.

SYSTRA engineers and analysts used the output data to identify areas in the LIRR traction power system requiring reinforcement for future operations. Once these areas were identified, a number of engineering solutions were simulated to assess their effectiveness. These measures include:

• Increasing all substation nominal voltages to 750V,
• Utilization of Thyristor Rectifiers,
• Replacing Conventional Third Rail By Composite Rail,
• Replacing Conventional and Composite Rail by Aluminum Third Rail,
• Building Additional Circuit Breaker Houses, which allow traction power loads to be better shared across multiple tracks, and
• Building Additional Substations