What is this?

[carlos118]

I am asking about the two yellow blocks

Found on the Northern Line, looks connected to the conductor rails. Anyone know what this is / what it is used for?

 

[Mojo]

It detects the presence of traction current for display on a P Crid. This is a permanent current rail indicator device which are on tunnel walls or other standalone locations. These assets were installed by Tube Lines across the Jubilee, Northern and Piccadilly line and display the status of traction current.

 

[carlos118]

It detects the presence of traction current for display on a P Crid. This is a permanent current rail indicator device which are on tunnel walls or other standalone locations. These assets were installed by Tube Lines across the Jubilee, Northern and Piccadilly line and display the status of traction current.

Thank you so much! This answers my question perfectly!

 

[rebmcr]

It detects the presence of traction current for display on a P Crid. This is a permanent current rail indicator device which are on tunnel walls or other standalone locations. These assets were installed by Tube Lines across the Jubilee, Northern and Piccadilly line and display the status of traction current.

I guess this implies the prior existence of portable, temporary CRIDs that would have been used by engineering teams for safety checklists?

 

[bluegoblin7]

Yes, portable CRIDs (simply CRIDs) are an essential piece of kit for anyone accessing LUL track.

Despite the providence of PCRIDs on former Tube Lines/JNP lines, they were never fully signed off for use to replace the CRID.

More on a CRID here: https://www.unipartrail.com/wp-content/uploads/2020/04/st-crid.pdf

 

[MaidaVale]

As put above, It's a PCRID installed on the JNP lines only and are no longer (if ever) used for safety critical decisions.

Contractors accessing the track during engineering hours must use a regular CRID that they place themselves, and cannot rely on the information given by these PCRIDs. In most cases, they just display "Fault" now anyway.

Attached are images of a PCRID (left) and a regular CRID (right).

 

[Mawkie]

As put above, It's a PCRID installed on the JNP lines only and are no longer (if ever) used for safety critical decisions.

I think I read somewhere they are due for replacement with an updated version soon, but happy to be corrected.

 

[starlight73]

I think I read somewhere they are due for replacement with an updated version soon, but happy to be corrected.

Yes, they’ve awarded a contract to Drallim Industries for this (subscription only article which I can’t read, so that’s all I know!)

London Underground orders second-generation safety system

UK: London Underground has awarded Drallim Industries a contract to design, manufacture and service an enhanced version of the Permanent Current Rail Indicating Device. The permanently-fixed traction current status indicators are designed to reduce the risk of staff accessing the track when the...

www.railwaygazette.com

UK: London Underground has awarded Drallim Industries a contract to design, manufacture and service an enhanced version of the Permanent Current Rail Indicating Device.

 

[ThameslinkUser]

UK: London Underground has awarded Drallim Industries a contract to design, manufacture and service an enhanced version of the Permanent Current Rail Indicating Device.

The permanently-fixed traction current status indicators are designed to reduce the risk of staff accessing the track when the traction current is switched on, or when its status cannot be determined.

Drallim manufactured the original version from 2007.

Announcing the latest contract on February 26, the Sussex-based company said advances in high voltage and power backup electronics now offer the opportunity to replace the ageing installed base and to expand deployment to the whole London Underground network.

The second generation PCRID will be optimised for fast installation and swap-out maintenance, with a 90 h internal backup battery suitable for on-site replacement. It will be lightweight and robust with upgraded ingress protection ad Safety Level 2 certified, and will tolerate regenerated power.

 

[bramling]

Yes, portable CRIDs (simply CRIDs) are an essential piece of kit for anyone accessing LUL track.

Despite the providence of PCRIDs on former Tube Lines/JNP lines, they were never fully signed off for use to replace the CRID.

More on a CRID here: https://www.unipartrail.com/wp-content/uploads/2020/04/st-crid.pdf

LU seems to have had one of its corporate memory failures here.

So the purpose of a CRID was to allow engineering staff to go down on the track during engineering hours without needing to get confirmation from anyone regarding the status of traction current, essentially because there was (and is) no other way of determining the status of the traction current and to avoid the controllers receiving potentially hundreds of phone calls.

Yet now this seems to have morphed into using them to determine status during traffic hours for operating staff. LU doesn’t seem to trust their own staff to use the traditional method of seeking confirmation from the line controller, which says a lot about the robustness of today’s training (and perhaps recruitment).

Hence we now see oddities like emergency services wanting to see a CRID used (though of course with no guarantee that it will be used correctly) when there’s an SCD down in plain sight. Dear dear dear.

 

[starlight73]

Was their introduction related to 7/7? (I vaguely remember hearing a report that the fire brigade decided to wait before going into the tunnel because they couldn’t get confirmation that it was safe to do so.) Of course I could be completely wrong

I’m just curious about the history - not specifically for or against them.

Edit: just realised that Bramling’s post implies they weren’t related to 7/7, sorry