CT 2013 Attempt

[asrisaku]

Dear sir/madam

It's the tough year as I know. If anyone of you can give me any comments, I would appreciate that. I think the questions seem tricky and I am sure I have done the CT 2013 with mistakes somewhere.

Please kindly review it if possible. : 0 )

Best regards, arnut

[asrisaku]

Hi Guys again

I don't think that my first attempt is correct. Please find the new one.

Also comments please...

Note: I realize that CT2013 is much easier than other years and feel a bit shame on my attempt that my 1st attempt could not give 100% correct. It took a long process to me to learn things. Hopefully I can get some comments to improve my knowledge.

Best wishes, Arnut

[jenni.joseph9]

Hi,

Good effort.

In a Quick look, I found that you missed 221 point Normal, for Route 119 call on route.

Also, Overrun protection document related to UK main line standards, considers side collisions and not headon collisions. I am attaching that for your reference.

Can you please let me know the principle behind that overrun protection entry in your CT format. May be some new point for me to learn .

Many Thanks in advance.

[asrisaku]

Hi,

Good effort.

In a Quick look, I found that you missed 221 point Normal, for Route 119 call on route.

Aha! I made a silly mistake though I had a highlighted route in the layout. I frequently found that my mind could not focus on complicated tasks and made such and threw away easy marks. Thanks so much.

Also, Overrun protection document related to UK main line standards, considers side collisions and not headon collisions. I am attaching that for your reference.

Very useful for your help. I did not know that before. It is an eye opener for me.

Can you please let me know the principle behind that overrun protection entry in your CT format. May be some new point for me to learn .

Many Thanks in advance.

Actually I have 2-year experience in mainline in Thailand as a tester in control tables. The overrun protection is based on my understanding as track flanks in SRT project searched for any tracks that do not have signal protection.

Any more serious mistake? please...

[asrisaku]

Another query? How could you prevent headon collisions? Any suggestion?

[dorothy.pipet]

For Preventing head-on collisions there are several different cases (in no particular order):
[and assuming you're thinking about areas controlled by Track Circuit Block]
1) signalled moves from controlled signals - prevented by opposing locking from setting the second route;
2) bidirectional Auto sections - generally some form of additional locking such as a direction switch;
3) Train running away from sidings/depot/freight yard etc - we use trap points to direct the run-away train away from the main/passenger line;
4) where one of the trains is overrunning;
a. TPWS will mitigate this by applying the brakes in the overrunning train. TPWS is not fail-safe but having said that has proved itself reliable and is designed to stop an overrunning train before a collision point.
b. Flank protection may be provided by calling points which are not in the route to a position which protects the route, It's limited because you don't want to prevent valid parallel moves.
c. Swinging overlaps may be called to a preferred position in order to direct an overrunning train in a particular direction.
5) where both the trains have overrun: current UK Principles explicitly state that this situation is not considered when designing controls, however, any of the points under (4) above would apply individually to each train.

[asrisaku]

For Preventing head-on collisions there are several different cases (in no particular order):
[and assuming you're thinking about areas controlled by Track Circuit Block]
1) signalled moves from controlled signals - prevented by opposing locking from setting the second route;
2) bidirectional Auto sections - generally some form of additional locking such as a direction switch;
3) Train running away from sidings/depot/freight yard etc - we use trap points to direct the run-away train away from the main/passenger line;
4) where one of the trains is overrunning;
a. TPWS will mitigate this by applying the brakes in the overrunning train. TPWS is not fail-safe but having said that has proved itself reliable and is designed to stop an overrunning train before a collision point.
b. Flank protection may be provided by calling points which are not in the route to a position which protects the route, It's limited because you don't want to prevent valid parallel moves.
c. Swinging overlaps may be called to a preferred position in order to direct an overrunning train in a particular direction.
5) where both the trains have overrun: current UK Principles explicitly state that this situation is not considered when designing controls, however, any of the points under (4) above would apply individually to each train.

Thanks for your information. I'll read it carefully and if I do not understand, I'll come up with a question to you again.

[StrongLifts5x5]

Hi Folks

Regarding 212 points if the signaller keys 212R he can still set 138A(M)- 132B(M) so do 138A(M),136(B)M, 134B(M), and 132B(M) not also have to be in the R-N train detection clear box?

It would mean you would have both routes in both boxes so I'm not sure if its acceptable, the route boxes say "up main" but there would be nothing to stop a route set to 122 with 212R.

Or is the assumption that the points always called normal with a Up main route as its a terminal station?

[PJW]

To NR practice, 212 is in a simple swinging overlap beyond 122. If 212 happen to be lying N then when a route to 122 is set then it will remain N but if it happens initially to be lying R then the route will still set and the points will be left R. Even with that route remaining set then 212 remain free to be swung either on the points individual switch or by setting a route forward from 122.
The overlap is simple in that there are the same aspect controls in either lie- no additional tracks, points or opposing routes to consider for one differently to the other.

The locking that there will be is purely because of how close 212 is to 122 signal; there will be "time of operation" locking to prevent point movement when there is a chance that there could be a SPAD that might then reach the points in mid-stroke. This is symmetrical N to R and R to N; the points are locked upon occupation of DH when there is overlap locking and released once DH has been occupied long enough that the train has been timed to a stand.

Hi Folks

Regarding 212 points if the signaller keys 212R he can still set 138A(M)- 132B(M) so do 138A(M),136(B)M, 134B(M), and 132B(M) not also have to be in the R-N train detection clear box?

It would mean you would have both routes in both boxes so I'm not sure if its acceptable, the route boxes say "up main" but there would be nothing to stop a route set to 122 with 212R. With no condition within the aspect level of the signal, then there is no need for "counter conditional" in the point locking.

Or is the assumption that the points always called normal with a Up main route as its a terminal station?

[laz07]

Hello,

For facing points in the overlap we tend to have an alternative overlap selected by a forward route set rather than a swinging overlap. I am more used to SSI control tables using subroutes for the locking, but for the 212 points example, if you wanted to declare that the overlap over 212R was only used if 122AM was set before the route reading up to 122 was set, is this an acceptable way of representing it on the irse points control table format?

Any comments appreciated.