New Jersey Department of Transportation Bureau of Research recently carried out a limited study on the Elimination of Weight Restriction on Amtrak, NJ Transit and Conrail Lines.
This report FHWA-NJ-2012-003 looked at the impact of increasing the weight of freight rail car on various passenger lines in New Jersey. Most of the railway bridges in New Jersey were built prior to World War II and are not designed for this increased railcar weight. Various methods are currently used for evaluating existing railway bridges, including
• Traditional load rating method based on AREMA specifications;
• Finite element modeling method; and
• Field testing method using various types of sensors such as strain transducers, Laser Doppler Vibrometer (LDV) to measure deflections, & accelerometers.
Only five critical bridges were selected for the prior study which is not a representative sample of the old and defective bridges.