Modjeski and Masters served as design engineer of record for the West Colton Transfer Table Replacement Project for Union Pacific Railroad operations at the West Colton Yard in Colton, CA. The team was tasked with designing a replacement table that would alleviate current operating concerns of skewing and jamming against the pit wall and have an extended service life. Using our expertise in heavy movable structures, the team of mechanical, electrical, and structural engineers designed a table that meets operational needs and American Railway Engineering and Maintenance-of-Way Association bridge specifications, and has an increased service life, making it robust and easily maintained.
The existing transfer table was equipped with 8 total drive motors/trucks. All 8 motors were connected in parallel to and controlled and operated by a single control drive. This setup was not ideal for skew control of the transfer table, as there is no way to separately control each motor/drive to correct for skew.
Using M&M’s expertise in movable bridge design, the new table design uses concepts of a modified movable bridge. It features two independent drive systems (master/slave) that each drive two wheels from one motor, very similar to the drive system in a tower drive vertical lift bridge. This setup allows for the speed of each drive assembly to be adjusted based on position feedback devices to mitigate table skew. The transfer table moves laterally to move locomotives from the track to a maintenance bay.
Another unique aspect of the project is that unlike bridge projects where certain components are built and tested, this entire table was built offsite and ran test loads prior to being transported by truck to the Colton facility.
Construction staging was carefully coordinated to allow the maintenance yard to remain operational while the new table was being installed. This resulted in a successful table replacement with minimal disruption to operations.