Rebuilt contactors maintain rapid transit services

Edited by the Engineeringtalk editorial team Apr 5, 2005

An arrangement with Rowe Hankins Components for the rebuild of heavy-duty contactors, has provided Serco Metrolink engineers with a solution to a potentially serious dilemma.

Serco Metrolink, Manchester's pioneering rapid transit system, performs miracles.

With a fleet of 32 twin-car articulated units, the company provides a 6min peak-time service, over a 37km network, and carries 52,000 passengers per day.

Uptime is a serious issue as there is very little spare fleet capacity.

An arrangement with Rowe Hankins Components for the rebuild of heavy-duty contactors, has provided engineers with a solution to a potentially serious dilemma.

To meet service obligations under their contract with Greater Manchester Passenger Transport Authority, Serco Metrolink must supply 29 twin units at peak time and 26 for daytime operation.

Alstom is currently contracted to replace floors and window seals on the Phase 1 vehicles and therefore one unit at a time will be out of service while improvements are made.

Routine servicing may take a further unit out of use and so there is only a small margin of spare capacity to meet rush hour demands.

The 26 Phase 1 vehicles sets are now 13 years old.

These vehicles have proven reliable under intensive use.

Metrolink's objective is to maintain maximum availability by ensuring maintenance is planned, including the timely replacement of critical components and wearing parts.

Seven heavy-duty contactors per car set provide a 750V DC power feed to the motor circuits.

Failure or deterioration in the contactors could disable the vehicles or severely affect their performance.

The contactors are of a traditional electropneumatic type, originally supplied by GEC, but now out of production for more than 10 years.

Refurbishment is much more cost effective than replacement both in initial cost and in avoiding the need for modification to existing equipment cases.

As OEM supplier and refurbishment contractor for Secheron heavy-duty rail contactors, Rowe Hankins has the experience and special equipment needed to fully rebuild and test, with rapid turnaround.

The refurbishment process involves the replacement and renewal of all wearing parts including contact tips, springs and pneumatic seals.

The calibration of the overload trip mechanism is checked, using a 5000A current tester and adjustments made if necessary.

Testing before and after refurbishment confirms performance improvement.

By agreement with Serco Metrolink, Rowe Hankins provides a 48-hour turnaround on all refurbished contactors.

This ensures that cars are rapidly returned to service so that Metrolink meet their service obligations.

Rowe Hankins have similar contracts for the refurbishment of Secheron contactors on vehicles on London Underground's Central Line.

Again, this provides an additional resource to the in-house engineering team, allowing service programmes to run smoothly and vehicles to be returned to service quickly.

The company also provide rebuild services for circuit breakers and upgrade services for on-train monitoring and recording (OTMR) equipment.

Rowe Hankins has developed a new approach to meeting the engineering needs of the rail and rapid transit industry.

Total reassurance engineering (TRE) is the description given to a raft of services to vehicle builders, operators and service contractors that offers flexibility in supply and maintenance with a promise of lifetime support for critical power and safety systems.