Pi Testing (metal To Metal) For Indian Railways

1.

Introduction This pamphlet explains in brief the basic steps for testing of selection table of PI&RRI (Metal to Metal) installation, which is useful during commissioning as well as periodic testing of such installation. 2. Main Signal 2.1 Back Locking • Clear the concerned signal. Drop & Pick up each TR/TPR in the route of the signal, its overlap and isolation. • The signal should go to danger when TR/TPR is dropped and should be off when track circuit is picked up. • It ensures that the concerned track circuits have been taken in GR2 circuit. • Fail the TR/TPR permanently and after a few seconds pick it up. • The signal should not re-clear. It indicates that GR1 has dropped. • Fail the TPR during testing and do three button cancellation with TPR failed. No such sub route should get released. • Again do three button cancellation and keep GN and UN buttons pressed and pick up the TPR being tested. • All sub route and Ovs should get released as soon as the TPR is picked up. In case the track circuit is berthing track, Overlap track or isolation track, the routes will get released even with TPR dropped. • In case of dead approach signal, the above testing must be done after the final timer relay AJTR3 has picked up. Repeat the above testing till the last OV track.

2.2 Red lamp protection • Take off the concerned signal and remove the RG fuse of the signal ahead. • The indication of the ahead signal should be flashing red. • The rear signal should go to danger • Re-insert the fuse • The rear signal should not re-clear 2.3 Route indicator testing • For all signal movements with diversion remove the route indicator lamps supply fuse. • The indication for route indicator on panel should start flashing. The signal should go to danger. • Ensure that route lamp checking relay (UECR) does not pick up with three or more lamps fused in the junction type route indicator • Re-insert the fuse • The signal should re-clear. 2.4 Proving of points in the route • Take off the concerned signal. Flash (fail) each point in the run(route) of the signal, its overlap and isolation as per selection table. • The signal should go to danger, when point is failed and should re-clear when point indication is steady. • This ensures that the concerned points have been taken in GR2 circuit. • Fail point permanently and after few seconds pick it up. • The signal should not clear. This indicates that GR1 has dropped. 2.5 Crank handle interlocking

•

Clear the signal and try to give slot (control) for concerned crank handle key lock relay (KLR). • The slot should not go and signal should not go to danger. • Fail the crank handle key lock-checking relay (KLCR) coming from site. • The crank handle indication becomes flashing red on the panel. • Give the slot for concerned KLR and try to clear the signal. Signal should not clear. • For PIs the route will initiate and for RRIs the route will set but the point will not get locked and the point will not operate in chain group operation. Indication on the panel flashing white. • In both cases the point must be free for individual operation after slot for concerned KLR is given. • Extract the KLR key • Indication in the panel flashing red. 2.6 Sub routes and overlaps • Clear the signal and normalize each sub route one at a time manually or by (EUYN) emergency route cancellation button. • The signal should go to danger and indication of that particular sub route should extinguish on the panel. • Normalize the (OV) overlap relay. • The signal should go to danger. • Alternatively remove the overlap common fuse and then try to clear the signal. • The overlap will not set and signal will not clear. 2.7 Approach locking

•

Clear the signal. Fail the approach track. Do three-button cancellation. • The approach lock timer will start. • Fail each track, which is part of approach track. • Try to do three button cancellation with the timer flashing. • It must not be possible to release the route • After the timer becomes steady try to release the route by three buttons. • The route should get released. 3. Points 3.1 Track locking • Fail the track circuit with the other track circuit of point/ crossover as pick up • It must not be possible to individually operate the points through WWN common points button • It must be possible to operate the point through EWN and EWN counter must increment. • Fail the other track circuit with first track circuit of a point /cross over as pick up and repeat testing as above. Point operation through WWN should not be possible as above. • When the both track circuits of a point/crossover are picked up it must not be possible to operate the point by EWN. 4. Subsidiary Signal 4.1 Calling on Signal • For testing of calling on signal after clearing calling on signal testing of points proving, KLRs testing, sub route

testing, station masters slide testing must be carried out. With calling on given all conflicting signal must be locked. • Drop the calling on /approach track of the concerned signal. Press buttons on panel to clear calling on signal. The calling on signal should be clear only after two minutes after calling on /approach track being occupied and should go to danger when this track circuit is picked up. • At many places a signal and calling on are conflicting i.e. “A” sign clears only for straight route and calling on only for diversion. The same must be tested. 4.2 Shunt Signal • For testing of shunt signals, track circuits testing (Back locking) except berthing, OV track and isolation track must be done. Testing of points proving, KLRs testing, sub route testing, approach locking must be done similar to testing of main signal. • Fail points and KLRs and again pick them up, the shunt signal will re-clear, there is no cascading in shunt signal. 5. Station master’s slide testing • Pull each slide of slide frame, the concerned YR only will pick up and YNCR must drop and YNCPR must remain up as route is not set. The panel indication must be checked accordingly. • Fail the first track before the berthing track, the concerned YR must drop and if sub route is set, YR must not pick up even if track is picked up.

•

Set the sub route and pull the station master’s slide, the concerned YR must not pick up as YNCPR has dropped. Thus YR will pick up only when sub route is not set. 6. Testing of Gates • The concerned signals, gate signals, “A” sign, calling on, shunts signals must go to danger when the XCKR of gate is failed. • It must not be possible to open the gate with sub route or overlap leading over it is set for any line or when only “A” sign is given with route released, the slot for gate opening must not go and the signal should not go to danger. • When gate is open, it must be possible to initiate the route and operation should take place up to GLSR. 7. Testing using simulation panel The following testing shall be done using simulation panel as per control table. 7.1 Random check • Check up that indirectly conflicting signals cannot be taken off simultaneously. • Keep one or more points in the route in unfavorable position and try to take off signal, which should not be possible. • For taking off calling on signal, keep all the track circuits in dropped condition including the approach track and check whether it could be taken off. For automatic signaling territory the calling on should clear only when the first track ahead of the signal is picked up. For other than automatic territory, the calling on signal should clear.

•

Special attention may be given for overlap point detection whether required or not as per circuit.

 It is clarified that information given in this pamphlet does not supersede any existing provision laid down in “Signal Engineering Manual”, Railway Board publications and RDSO publications. This document is not statutory and instructions given in it are for the purpose of guidance only. If at any point contradiction is observed, then SEM, Railway Board and RDSO guidelines or Zonal Rly. instructions may be followed.