Light Rail Tub Crossing Repair

light rail tub crossing repair by CJGeo

Crossing Use:  

Light rail, suburban arterial street

Problem:

A suburban grade double crossing was rebuilt to address poor drainage infrastructure in the area.  This included installing two different culverts adjacent to the crossing panels, and then resetting all of the panels which had to be removed for the culvert installation.  During routine track inspections, the panels showed signs of deflection up to one inch with rail traffic.  The system’s track division was concerned that pumping of the crossing panels would lead to destabilization of the base, and settlement.  At the lower elevation end of the crossing, there was extensive evidence of sub base material being pumped out from under the crossing within two weeks of the crossing reconstruction.  368 track feet were affected.

Constraints:

Work had to be completed during non-revenue hours, between 0200 & 0430 over two nights.  There was also a high probability of the voids below the panels being waterlogged.

Solution:

High density polyurethane grouting to stabilize the grade crossing panels.  Specially-formulated hydro-insensitive void filling (high-mobility) grout was proposed in order to ensure complete filling of voids below the panels, whether waterlogged or dry.  

Result:

 CJGeo successfully stabilized the crossing during the two night work period.