Track Density (Tonnage) Estimation for Commuter Railroad

Commuter railroads do not typically consider their output in terms of million gross tons (MGTs) carried, and typically have negligible freight activity.  However, tonnage estimations can be important for assessing turnout and curve rail replacement, and resurfacing needs.  On behalf of an infrastructure owner of mixed-traffic trackage in a commuter district, we estimated the track density on a track and block level.  Starting with electronic train movement records, we designed a heuristic to automatically filter out questionable data, and provide reasonable estimates for use in their place.  This was then combined with planned train-level consist data and seated-load gross equipment weights to determine MGTs attributable to passenger trains and EMU equipment.  For road freight trains, we used one year’s worth of freight train manifests to determine tonnage carried, marrying this with train movement data to determine their routing.  For unit trains (that load or unload within the territory), and local trains (that pick-up and set-out loads within the territory—negligible volumes), we tracked the tonnage changes en-route where this was deemed a significant factor in the total MGT estimate.  On several mainline track segments, freight MGT was found to be between 30%~35% of total MGT and a significant contributor to track wear, despite this being a very busy commuter district that only saw 4~7 road freight trains per day (compared to upwards of 800 daily commuter train-starts).  This finding triggered additional management interest in freight activity.