https://irse.signalpost.org/ Fri, 19 Jun 2026 10:53:29 +0000 MyBB https://irse.signalpost.org/showthread.php?tid=2312 Thu, 06 Sep 2018 11:31:29 +0000 tfly86]]> https://irse.signalpost.org/showthread.php?tid=2312 Find attached my attempt on the track circuit calculation question from 2013. This attempt actually took me an hour- so needs refining for exam conditions. Could anyone offer some tips for streamlining my answers for a similar question otherwise I would need to avoid on the day.

Also if anyone could offer any calculations and/or description of why the relay drop current is 68% of the relay pick current. I understand that it is to do with the electromagnetic properties of the coil, but would be helpful to understand a little more, so I don't just carry on with the old "it is because it is" method of reasoning.

Please review and comment.

Question 4(2013)
Calculate the maximum track circuit length for reliable operation based on the following
parameters:
• Feed voltage 50V
• Feed end resistance 50Ohm
• Relay pick up current 0.4A
• Relay resistance 25Ohm
• Ballast resistivity 75Ohm.km

You should state any assumptions that you make and show your calculations [15 marks]
For the length that you have calculated, calculate the drop shunt value. [5 marks]
A track circuit with the same design parameters as above has had a number of failures of
showing occupied when clear. Briefly discuss the possible causes of the failure. [5 marks]

Thanks

Tommy]]> Find attached my attempt on the track circuit calculation question from 2013. This attempt actually took me an hour- so needs refining for exam conditions. Could anyone offer some tips for streamlining my answers for a similar question otherwise I would need to avoid on the day.

Also if anyone could offer any calculations and/or description of why the relay drop current is 68% of the relay pick current. I understand that it is to do with the electromagnetic properties of the coil, but would be helpful to understand a little more, so I don't just carry on with the old "it is because it is" method of reasoning.

Please review and comment.

Question 4(2013)
Calculate the maximum track circuit length for reliable operation based on the following
parameters:
• Feed voltage 50V
• Feed end resistance 50Ohm
• Relay pick up current 0.4A
• Relay resistance 25Ohm
• Ballast resistivity 75Ohm.km

You should state any assumptions that you make and show your calculations [15 marks]
For the length that you have calculated, calculate the drop shunt value. [5 marks]
A track circuit with the same design parameters as above has had a number of failures of
showing occupied when clear. Briefly discuss the possible causes of the failure. [5 marks]

Thanks

Tommy]]> https://irse.signalpost.org/showthread.php?tid=2310 Mon, 03 Sep 2018 14:30:42 +0000 tfly86]]> https://irse.signalpost.org/showthread.php?tid=2310
Question 3 (2012)
Describe with the aid of diagrams the operation of the following two systems:

• Joint less track circuit
  
• axle counter system [15 marks]
  

What are the advantages and disadvantages of each system? [10 marks]

Please can you provide comment.

Regards

Tommy]]>
Question 3 (2012)
Describe with the aid of diagrams the operation of the following two systems:

• Joint less track circuit
  
• axle counter system [15 marks]
  

What are the advantages and disadvantages of each system? [10 marks]

Please can you provide comment.

Regards

Tommy]]> https://irse.signalpost.org/showthread.php?tid=2302 Fri, 17 Aug 2018 04:37:29 +0000 Boris_MTM]]> https://irse.signalpost.org/showthread.php?tid=2302
Some feedback would be beneficial. I have done further reading on AC track circuits since attempting this question but would like to know if was on the right track on the general theory.]]>
Some feedback would be beneficial. I have done further reading on AC track circuits since attempting this question but would like to know if was on the right track on the general theory.]]> https://irse.signalpost.org/showthread.php?tid=2289 Thu, 12 Apr 2018 15:10:52 +0000 steak]]> https://irse.signalpost.org/showthread.php?tid=2289
Please review and comment.

Wasn't sure about considerations bit of a stab in the dark.
Wasn't sure whether to use Absolute block signalling for tail lamp, my example seemed shorter to explain plus can't see what suitable uses Absolute would have now.]]>
Please review and comment.

Wasn't sure about considerations bit of a stab in the dark.
Wasn't sure whether to use Absolute block signalling for tail lamp, my example seemed shorter to explain plus can't see what suitable uses Absolute would have now.]]> https://irse.signalpost.org/showthread.php?tid=2280 Tue, 06 Mar 2018 16:19:52 +0000 steak]]> https://irse.signalpost.org/showthread.php?tid=2280 Which signalling functions need to positively prove the presence of a train and which need to prove track clear?

Im struggling to answer/structure the answer and could do with some help in putting it into words.

Main safety functions I'm thinking are

• To prevent trains taking conflicting routes
  
• To maintain safe distance between trains
  
• Protect trains against driver error
  
• To ensure trains do not exceed their permitted speed
  

thanks in advance]]> Which signalling functions need to positively prove the presence of a train and which need to prove track clear?

Im struggling to answer/structure the answer and could do with some help in putting it into words.

Main safety functions I'm thinking are

• To prevent trains taking conflicting routes
  
• To maintain safe distance between trains
  
• Protect trains against driver error
  
• To ensure trains do not exceed their permitted speed
  

thanks in advance]]> https://irse.signalpost.org/showthread.php?tid=2248 Sun, 10 Dec 2017 08:22:12 +0000 PJW]]> https://irse.signalpost.org/showthread.php?tid=2248 https://irse.signalpost.org/showthread.php?tid=2245 Sun, 10 Dec 2017 07:55:49 +0000 PJW]]> https://irse.signalpost.org/showthread.php?tid=2245 https://irse.signalpost.org/showthread.php?tid=2118 Wed, 07 Sep 2016 12:57:31 +0000 magicmaciej]]> https://irse.signalpost.org/showthread.php?tid=2118
NR standard for EBI states that no cross bonding  (direct or indirect) is allowed between tracks of the same frequency.
Why this is an issue? I understand that impedance bond will block the frequency used for train detection and therefore this should not be a problem. Also with AC electrified railway almost everything is either directly or indirectly bonded to earth/rsc.

Cheers,

Magic]]>
NR standard for EBI states that no cross bonding  (direct or indirect) is allowed between tracks of the same frequency.
Why this is an issue? I understand that impedance bond will block the frequency used for train detection and therefore this should not be a problem. Also with AC electrified railway almost everything is either directly or indirectly bonded to earth/rsc.

Cheers,

Magic]]> https://irse.signalpost.org/showthread.php?tid=1938 Tue, 07 Jul 2015 09:19:51 +0000 StrongLifts5x5]]> https://irse.signalpost.org/showthread.php?tid=1938
However it apparently has issues identifying failing IRJ's in areas were common voltages are used on adjecant tracks and through P&C work.

Anyone have any experience or information on the Pearce Tester and as to why it would have these failings?? Or are there other methods more suitable for IRJ testing??]]>
However it apparently has issues identifying failing IRJ's in areas were common voltages are used on adjecant tracks and through P&C work.

Anyone have any experience or information on the Pearce Tester and as to why it would have these failings?? Or are there other methods more suitable for IRJ testing??]]> https://irse.signalpost.org/showthread.php?tid=1931 Tue, 09 Jun 2015 05:05:14 +0000 asrisaku]]> https://irse.signalpost.org/showthread.php?tid=1931
Another attempt, please feel free to make any comment.

Thanks in advance.

Best regards
Arnut]]>
Another attempt, please feel free to make any comment.

Thanks in advance.

Best regards
Arnut]]> https://irse.signalpost.org/showthread.php?tid=1895 Thu, 19 Mar 2015 01:16:55 +0000 asrisaku]]> https://irse.signalpost.org/showthread.php?tid=1895
I have tried to practice the axle counter question.

It would be good if any one can give me any comment.

Thanks!
Arnut]]>
I have tried to practice the axle counter question.

It would be good if any one can give me any comment.

Thanks!
Arnut]]> https://irse.signalpost.org/showthread.php?tid=1893 Mon, 16 Mar 2015 14:43:31 +0000 Archie]]> https://irse.signalpost.org/showthread.php?tid=1893
Any help would be much appreciated.

Many thanks]]>
Any help would be much appreciated.

Many thanks]]> https://irse.signalpost.org/showthread.php?tid=1673 Wed, 05 Mar 2014 16:17:50 +0000 Chall1986]]> https://irse.signalpost.org/showthread.php?tid=1673
Can anyone point me in the right direction, I need some information on Aster '1 watt', Aster 'Type U' and EBI200 tracks. I need to compare their operation and advantages.

I know very little about the Aster systems, apart from they are analogue and were replaced by the EBI200 tracks which are digital.

I have the Bombardier manual for the EBI tracks which explains what frequencies can be used where and ETU / TU's are installation etc.

I would appreciate any kind of information.

Thank you]]>
Can anyone point me in the right direction, I need some information on Aster '1 watt', Aster 'Type U' and EBI200 tracks. I need to compare their operation and advantages.

I know very little about the Aster systems, apart from they are analogue and were replaced by the EBI200 tracks which are digital.

I have the Bombardier manual for the EBI tracks which explains what frequencies can be used where and ETU / TU's are installation etc.

I would appreciate any kind of information.

Thank you]]> https://irse.signalpost.org/showthread.php?tid=1625 Sun, 12 Jan 2014 17:11:56 +0000 Fat controller]]> https://irse.signalpost.org/showthread.php?tid=1625 I have recently been considering the ups arrangements used on recent projects.
We install PSP's, fully fitted with ups systems then at the REBs fitted with Axle counter evaluators we fit another UPS. Why?

My understanding is the ups at the ACE allows time for the signaller to be alerted to a power failure to bring trains to a stop. Typically 10 min hold up time.

My understanding of the PSP UPS is to allow time for the technician to attend and reconfigure the source. Manual reconfiguration. Typically 30 min.

Why can't the ACE rely on the line side power if it is maintained by a ups at the PSP?

Any thoughts?
FC]]> I have recently been considering the ups arrangements used on recent projects.
We install PSP's, fully fitted with ups systems then at the REBs fitted with Axle counter evaluators we fit another UPS. Why?

My understanding is the ups at the ACE allows time for the signaller to be alerted to a power failure to bring trains to a stop. Typically 10 min hold up time.

My understanding of the PSP UPS is to allow time for the technician to attend and reconfigure the source. Manual reconfiguration. Typically 30 min.

Why can't the ACE rely on the line side power if it is maintained by a ups at the PSP?

Any thoughts?
FC]]> https://irse.signalpost.org/showthread.php?tid=1624 Sat, 11 Jan 2014 13:58:37 +0000 Archie]]> https://irse.signalpost.org/showthread.php?tid=1624
Many thanks in advance.]]>
Many thanks in advance.]]>