LAMP CHECKING RELAYS - ECRs - Part 27

LAMP CHECKING RELAYS (ECRs) -> 

• DECR
• HECR
• RECR
• UECR
• SHUNT ON ECR
• SHUNT OFF ECR. 
• CALLING ON ECR.

1. PROCEED ASPECT LAMP CHECKING RELAY(DECR)

- To understand DECR first take Yard diagram .

Lets take OFF signals for run through for Main line. 

Thereby S1DR, S1HR picks up. Through the picks up contact of S1DR, S1HR, its repeaters S1DPR, S1HPR picks up at signal location.

An 110V AC is applied to S1DG lamp through S1-DECR coil, HR, DR and DPR front contacts. 

Thereby S1DG lamp glows and the DECR relay picks up. Through DECR front contact, a green indication is provided in the S1 signal aspect on the panel.

Suppose S1DG Lamp fail to glow , then cascading circuit will work.

Means through S1DECR  back contact , S1HG(Yellow aspect) will glow  and S1HECR is picked up.

Suppose S1HG Lamp fail to glow , then cascading circuit will work.

Means through S1HECR  back contact and S1HG front contact ,the supply is applied to S1RG(Red aspect) will glow  and S1RECR is picked up.

2. Caution Aspect Checking Lamp (HECR) Circuit.

- Default S1 RG aspect will be glowing.

Suppost S1 signal is taken Off for Loop Line, its caution aspect controlling relay (HR) pickup contact ,thereby the caution aspect repeater /proving relay (HPR) at signal location picks up .

Through the pickup contact of S1HR , S1HPR, back contact of S1DECR and S1HECR coil, 110VAC is applied to S1HG Lamp.

Thereby S1HECR picksup and corresponding circuit indication is provided in the signal aspect on the panel.

Suppose S1HG fails to glow, then cascading arrangement enable the S1RG lamp to glow.

3) ON aspect lamp Checking Relay (RECR) circuit.

When a signal is not taken OFF , Through the back contact of HR and RECR coil , the supply is extended to S1RG.


The S1RG lamp glows thereby S1RECR is pickup , the corresponding indication is provided in the signal aspect on the panel.


4) Route Lamp Checking Relay (UECR) circuit.

When Home signal S1 is taken OFF for the Loop line, then the signal control relay for route (S1UGR) picks up in the relay room, which energises its repeater S1UGPR at signal location box.

The 110 AC Volt is applied in parallel to S1 route lamp (5 Numbers) through the front contact of S1UGPR and S1UECR coil. 

When Minimum three lamps are burning in the route , then S1UECR picks up.

Through the S1UECR front contact , S1UECPR is picked up at the relay room and the corresponding route indication is provided on S1 signal on the panel.

For picking up UECR minimum 3 lamps out of 5 should glow in the route.

5) SHUNT ON ECR:(In Independent Shunt Signal)

When a signal is not taken OFF , the SH201 HR will be in dropped condition . 

Through the SH201 HR back up contacts and SH201 ON ECR coil, the supply is extended to SH 201ON aspect lamp and SH 201 pilot lamp.

When the Both lamp burn , the SH 201 ON ECR is picked up and the corresponding indications are provided on the SH 201 signal on the panel.


5) SHUNT OFF ECR

Through SH201 HR , SH201 HPR front contact and SH201 OFF ECR coil, the supply extended to SH201 OFF aspect lamp and it burns.

Through HR front contact and SH 201 OFF ECR coil, the supply is extended to SH 201 pilot lamp and its burns.

Then SH 201 OFF ECR is picked up and the corresponding indications are provided on the SH201 signal on the panel.

TPR Circuit and Concept of Cross protection- Part 26

TPR Circuit:

- TR is normally present at Location Box.
- TPR is placed at Relay Room.
- TR and TPR are connected by an underground signalling cable.
- Two front contacts of TR are used for double cutting and the back contact of
  TR is used for cross protection and TPR is picked up in the relay room.

CONCEPT OF CROSS PROTECTION

Cross protection is an arrangement by which any vital relay such as HR, WNR, WRR is prevented from picking up, in case a foreign feed appears on relay terminals when the conditions are not favorable for the relay to pick up.  

This is achieved by shunting the vital relay coils with the contacts of those relays, which are not favorable for the picking up of relay.

For example while ALSR is in pick up condition, the concerned HR should not pick up.   For this HR relay is shunted with ALSR front contact.

When 1 ALSR is picked up if feed appears on the HR coil, then it gets short circuited through 1ALSR front contact and HR cannot pickup.

Similarly, WNR/WRR should not pick up when WLR is dropped.  

The cross protection arrangements for WNR/WRR is: -

This wiring arrangement also ensures the integrity of cross protection loop i.e., if the cross protection loop get disconnected at either end of the cross protection contact, the circuit for the relay also gets disconnected.

CRANK HANDLE INTERLOCKING CIRCUITS (CHLR/CHR) - Part 25

CRANK HANDLE INTERLOCKING CIRCUITS (CHLR/CHR) 

Purpose of Crank Handle:

- Where point motors operate points, crank handles(CH) are provided to facilitate operation of points manually in case of point failure or maintenance.

It is not possible to provide CH interlocking for every point individually.  At the same time it is not proper to have only one crank handle common for all the points also.  Therefore, points are grouped to achieve optimum flexibility. 

Crank handle interlocking with signal and points 

      (a) Whenever a signalled movement has to take place over the points it will not be possible to release the concerned CH which is kept locked inside an electrical key transmitter (HKT/RKT/EKT).   

      (b) When the crank handle is OUT it shall not be possible to 
            − Operate the points from panel.  
            − Clear any signal concerned. 


      (c) It shall not be possible to insert the crank handle taken out from one group in any other group point machine. 


To achieve the above interlocking, the crank handle should be chained and welded to the EKT key. When the key is inserted in the EKT and turned to clockwise, and the SM acknowledge, thereby the crank handle IN indication light up and crank handle in proving relay CHLR picks up and sticks through its own front contact. 

- CH should be sealed and kept in Panel room.
- In some cases CH is provided at Location Box , In that case the Location will be locked and the key shall be kept in the personal custody of the SM on duty.


CRANK HANDLE ZONES AND WARDS

The points in yard are grouped in different zone for maintaining the yard flexibility.

- In this yard point no 52 and 53 are grouped under CH1.
- If CH1 is taken out , Sown movement signal alone are affected. 
- Up side signal can be taken for traffic.
- The point in the Yard are divided into groups and to distinguish a particular group , CH with different wards shall be used.


Crank handle free relay -CHFR

When all the concerned signal are in normal 
i.e. LRs dropped, 
then CH1FR will be in energized condition. 
Then crank handle free indication will be in lit condition in the CH box. 
There by it gives indication to SM that CH1 can be extracted if need arises. 

OR

When GN + UN -> Pressed and released simultaneously,
Then LR Picked up.
And Drops the Crank Handle Free Relay (CHFR)
Thereby the CH free indication is extinguished on the panel.
Thereby SM understands that CH1 can be not be extracted unless the signal is normalized. 

INDICATION CIRCUITS OR PANEL ILLUMINATION CIRCUIT- Part 24

INDICATION CIRCUITS OR PANEL ILLUMINATION CIRCUIT

1) Route Set and Lock Indication Circuit

- Panel being an interface between yard status and the station master. It Pay an important role in smooth working of a train.

- When route is not set, no indication is given on the panel.

-  When a signal is take OFF, the route is set and locked,then a row of white/ Yellow lights light up the whole length of the route including overlap.

- Many time the same track circuit shall be common to many routes, but the indication circuit is designed in a such a way that while the route strip lights get illuminated for a route to which it is a part and it is not illuminated in any other situation.

- These white/yellow strip lights are given through the back contact of ALSR and the relevant track circuit relay(TPR) front contacts.

-  When the train occupies the track circuits the lights turn to Red through the TR back contact. 

- The point indications are given through point indication relay front contacts and signal indication through lamp proving relay, front contacts.

2) Track Indications :

- Track occupied indications(Red light) are given through the back contact of TPR.  

- This should appear at all times whenever a track is occupied, irrespective of route set or not. 

- Two led or more are given to overcome the problems due to led failure. 

- Here R means Red(Occupied) and W means White(Not Occupied) for Track no 1T

- R2 is nothing but a Group Red light for track no 1T 

- When R2 then 1TPR drop and when W2 then TPR up

-If one led fails at least other will maintain the indication. “Track circuit occupied” indication is very important for safety point of view. 

Example

Circuits: When Track is not occupied

Circuits: When Track is occupied.

3) Point Indications :

- When a point is set and locked in N/R position, then two white/ Yellow strip lights are used to indicate the points position on the panel.

- Point indications are given through NWKR/RWKR front contact.

- Point free indication can be given through WLR contacts.  

- Point locked condition can be given with WLR dropped condition. 

- Point flashing indications are also given. Respective indication either Normal or Reverse will flash during the operation of point or due to failure.

Example:

Suppose take an example that we have one point in the yard whose number is 11 i.e Point 11 which is set and Lock in Normal condition.

Then 11A and 11C white strip light will be lit as per the given condition.

If Point in Normal then

If Point in reverse then

11 G -> 11RWKR(↑) and 11ATPR(↑)
11E -> 11RWKR(↑) and 11BTPR(↑)

Flashing indication during point operation.

The point indication remains flashing when the point is setting to either position till it is set ans lock, after which it become steady.

The Point Operation command is extended to point location only after the point indication relay NWKR, RWKR, NWKPRs, RWKPRs, NWSRs, RWSRs are dropped.

Therefore during the point operation , the white lights strip lights through the back contacts of indication relays(NWKR(↓) RWKR(↓)) will flash to whichever position the point is going to be set. On completion of any operation , when the point is set to normal and reverse , the indication become steady.


Example : Take the above yard and write the Point indication circuit of point number 51.

4) Flashing Indications


- Flashing indications are also given to indicate that the point is under operation or point indication has failed.  

- Suppose flasher fails and get stuck in high level then point failure indication will show steady instead of flashing.

- Flashing supply is derived from a mercury pendulum flasher unit or flashers

5) Signal Aspect Display:

Two methods of signal indication are prevalent in INDIAN RAILWAY 

These are:

1. ON and OFF aspect are displayed on the panel.
2. All aspects are available at the signal are replicate by the corresponding colour indications on the panel.  

Take the above yard diagram(example for S12) .

- C12 ECR (UP)

and the circuit are:

SIGNAL CONTROL RELAY CIRCUIT - Part 23

SIGNAL CONTROL RELAY CIRCUIT

Signal control circuit (HR)

The second stage of interlocking is carried out at signal clearance stage i.e. at HR stage. 

To design signal control circuit (HR) the following condition are to be proved. Lets Take off the Home signal S2 to Main line to study those condition.


(At HR stage all the conditions to be satisfied for clearing a signal are proved.) 

1. The SMs Key inserted and turned to normal to authorised operation i.e (SMR/SMCR (↑))
2. Crank handles are  ‘IN’, i.e. proved by CHLRs(↑)  and CHFRs(↓).
3. Sequence Route Release Relays have de-energized after the last train movement (UYR1, UYR2 etc., are down) (In Southern Railways UYR1 and UYR2 are called as TSSLR and TPZR respectively).
4. No signal cancellation is initiated i.e. JSLR(↓)or JS(↓).
5. Calling On signal is not initiated, which is proved in case calling ON signal is provided below the Main signal. 
6. Interlocked LCs if any in the Route and overlap are locked and closed against Road traffic (LXPR (↑)) and held locked till the passage of that train is over. 
7. Conflicting signals are at ‘ON’ is proved by proving the front contact of ASRs or back contacts UCRs of conflicting signals. 
8. All points in the route, overlap and isolation are set and locked i.e. Concerned NWKRs, RWKRs are in (↑) condition. 
   
9. Concerned to its own signal i.e.
   
10. All Back lock and controlling tracks are clear i.e. TPRs concerned are up.
    
11. Route Checking Relay UCR is (↑)
12. One Signal one train movement TSR (↑)
13. ALSR, OVSR, TLSR/TRSR (↓)
14. Signal ahead is not blank  (GECR(↑)or RECR/HECR/DECR(↑) in parallel) 
15. Route Indicator lamps are not lit for straight line (UHRs / UGRs and UECR (↓)) (compulsory in case of Junction type Indicator) 
16.  Route Indicator lamps are lit for loop lines (UGR or UHR and UECR (↑))
17.  Sidings in the route & overlap are kept normal and held (siding KLPR/NPR (↑)). 
18.  Cross protection is provided for the signal control relay, by the Front contact of ASR or Back contact of UCR. These contacts are not favorable for signal clearance. 
19. Double cutting is provided by UCR(↑)& ALSR(↓)and LXPR(↑)when LC gate is in the route
20. Signal Button is in Released condition(GNR(↓) )
21. Signal control relay (HR,UGR, DR) are made slow to release.

Signal Control Circuits HR, HHR, DR, CO-HR

The caution aspect of a signal is controlled by HR.  

Attention aspect and clear aspect are controlled by HHR & DR respectively. 

The ‘ON’ aspect (Red) is maintained through drop contact of HR.  

For Advance starter, the `ON’ aspect is controlled by DR drop and for distant signal the normal aspect (ON) is single yellow, controlled by HHR & DR drop. 

DR Circuit

Let us take OFF signal Number S2, S3, and S11 for Run through M/Ln.

Condition for S2DR to pick up:

1. S2UECPR(↓): its own HR is in picked up condition.
2. 3DR(↑): M/L DR is picked up.
3. 3DECPR(↑): on Negative Line. M/L starter proceed  aspect in burning.
4. Cross Protection is achieved by back contact of 3DECPR.



UGR Circuit:

Whenever a junction type route indication is used on a Home signal and if home is taken off to a loop line, then UGR is energised first.

Then 110 V AC supply is extended to the route lamps and UECR picks up when max three route lamps are burning. Then only HR is picked up through front contacts of UGR and UECR.


CO-HR Circuit:

- Now a days calling on signal are used very widely to increase the efficiency of signal system. Calling On signal is an emergency manager , in the sense that , this is used when the main signal above has failed.

- Calling on signal is taken Off even for receiving a train on an occupied line. therefore it is useful to deal with traffic during track circuit failure also.With calling on signals, the detentions are minimized .

- To study the features of calling on signal HR, let us take OFF calling on signal c-2 B to loop line.

1.  It is desirable to provide track circuits of a sufficient length in rear of the signal and a time delay circuit to ensure that the CO signal is taken OFF only after the train has been brought to a stop .To achieve this the train has to occupy the calling on track provided at rear of the signal and stop at the foot of the signal . The calling on signal is initiated and cleared after 120 sec.
2. The calling on signal shall not be capable of being worked at the same time as the main signal above or shunt signal below it, if any
3. A calling on signal shall  detect all points in the route, which the main signal  above detects excluding those in the overlap.
4. Route indicator above the main signal is not lit for calling on signal.
5. It is not required to prove any track circuit in Route and overlap for calling on signal clearance. However other conditions related to interlocking shall be the same as that of main signal above it.
6. On passage of the train , the calling on route get released on cancellation of calling On signal after a time delay of 120 sec. Sometime a sequential route release may be provided for route release of calling on signal.

PROVING OF THE ASPECT OF SIGNAL AHEAD (GECR) - Part 22

PROVING OF THE ASPECT OF SIGNAL AHEAD (GECR)

- In colour light signalling, there is a possibility of signal going blank due to lamp failures or power supply interruptions.

- This is undesirable since the Drivers are likely to miss the signal, which may result in an accident.

- To avoid this, it is a recent practice to prove the aspect of signal ahead in the rear signal. 

- For example, for clearing a home signal, any one of the aspect of starters in advance will be proved.

- GECR is made slow to release to cater for the aspect changing of signal in advance.

- 

 

Sectional Route Release Circuits (TLSR/TRSR) - Part 21

Sectional Route Release Circuits (TLSR/TRSR)

The Backed route locking provided on signal is sometimes cumbersome & time consuming since all the points in the entire route are locked till the train clears the full route it entered and the points cleared by a train can not be utilized for other movements. In big/Major yard with busy traffic the complete route locking hampers the efficiency and  causes un necessary detention. 

Hence another type of Route locking is adopted. 
In this system, the entire route is divided into small sub-route sections, according to the point zones. 
When the signals are given for a particular route all the sub routes sections in the route are locked, thereby the entire route is locked. 
But, the train on clearing each sub section of the route entered clears the locking effect of that route thereby those points cleared by the train can be utilized for other movements thereby increasing the flexibility of the yard. 

The first route section is directly controlled by the concerned ASR. 

The subsequent route sections are controlled by the TLSR/TRSR’s. 

For leftward movement i.e. from RIGHT to LEFT, TLSR and for rightward movement i.e., from left to right, TRSR is used. 

Depending upon the direction of signal movement, TLSR/TRSR’s are designed.

The TLSR/TRSR’s do the same job as that of ALSR and TLSR/TRSR picks up contact is used in WLR pick up circuit. 

When the signal is given, ALSR drops which in turn drops the required TLSR/TRSR’s to achieve complete route locking.  

ALSR picks upon clearing the first route section and the point(s) in the first route section becomes free. 

Subsequent route sections are still locked as the train clears the section by section and the points are released accordingly and they can be utilized for other movements. 

With TLSR/TRSR’S, the ALSR circuit shall be modified accordingly with back lock track circuits up to first route section or up to the first point. 


TLSR / TRSR ccts are normally adopted in big / major yards. (RRI’s)