Plasser's Quick Relaying System (PQRS)

It is essentially a semi-mechanised system of track renewal. PQRS consists of self propelled cranes which move on an auxiliary track of 3400 mm gauge having the same centre line as that of track to be relayed. These portal cranes are capable of self loading and unloading from BFRs. PQRS has following components-

1. Side Frames:-The machine contains two vertical side frames that house two vertical sliding frames.
2. Bridge:- Sliding frames are joined together with horizontal cross frame known as bridge. The Motive Power, hydraulic and electrical assemblies are installed over the bridge. The whole bridge is raised/lowered to facilitate lifting of panels.
3. Sleeper Gripper:- On the underside of the bridge, grippers to pickup sleepers is provided. Gripping of sleepers by its end is done by two angles welded to the grippers.
4. Rail Clamps:- On the end side of the frame scissors type clamps are provided to hold the rails/panels.
5. Turn Table:- To facilitate turning of portal cranes for placing it on the BFR and off tracking in mid section, a turntable is provided. On the BFR a wooden platform is provided to support the turntable.

Earlier, Portal cranes of model PQRS 2000-I has capacity of lifting maximum 5 t load. Maximum length of only 9 meter of prefabricated panel with PRC sleepers can be lifted by one portal crane. The later model PQRS 201 has capacity of lifting upto to 9 t. One such portal crane can lift 13 m long prefabricated panel with PRC sleepers.

General Data PQRS-2000-I,PORS-201
Engine: Deutz. Make 4 Cylinder 44 HP diesel engine Kirlosker Make air cooled HA-694, 75 HP
Drive: Hydraulic
Speed: 10 kmph-14 kmph
Lifting capacity: 5 tonnes-9 tonnes
Overall length: 2914 mm-3050 mm
Overall width: 3860 mm
Overall height above rail top: 4400 mm-4390 mm
Wheel base: 2400 mm-2400 mm
Wheel dia: 450 mm-450 mm
Weight 10 tonnes-12 tonnes

Briefly the sequence of operation for relaying with PQRS is as under:

Panels are fabricated with new sleepers and service rails in a Base Depot. These panels are loaded on BFRs in 3 or 4 layers. The existing rails in track are cut in lengths of 13 m.

Auxiliary track is laid to proper line and level with the new rail panels, if rail renewal is also to be carried out as part of track renewal. Otherwise, service rails are used for making auxiliary track.

PQRS rake is brought to site of relaying after getting proper traffic and OHE block.

Following three methods of laying of new panels are used depending upon site conditions:

- Pulling the PQRS rake
- Pushing the PQRS rake
- Parting the PQRS rake

Portals are unloaded on the Auxiliary track.

Old panels are removed and loaded on PQRS rake, ballast bed is scarified manually and new panels are laid at site by using portal cranes.

Proper ramp is provided at the beginning and at the end of the day's work.