Signalling Equilavent Units (SEUs)

[sam273]

Morning All,

I'm hoping this post catches the attention of some sort of signaling guru!

I am in the process of putting together some high level cost estimates for some major rail projects across the UK. Part of the one schemes I'm looking at requires that the existing signalling system is decommissioned and replaced with new and/ or a standard Line of Sight (LOS) system for LRT operation.

Typically, I understand that SEU rates are used to estimate signalling projects, but what is included in a standard SEU rate and how many SEUs are to be included per section of track? Is there any guidance or literature that exists on the topic? Google doesn't seem to be throwing any pointers.

 

[Joseph_Locke]

Morning All,

I'm hoping this post catches the attention of some sort of signaling guru!

I am in the process of putting together some high level cost estimates for some major rail projects across the UK. Part of the one schemes I'm looking at requires that the existing signalling system is decommissioned and replaced with new and/ or a standard Line of Sight (LOS) system for LRT operation.

Typically, I understand that SEU rates are used to estimate signalling projects, but what is included in a standard SEU rate and how many SEUs are to be included per section of track? Is there any guidance or literature that exists on the topic? Google doesn't seem to be throwing any pointers.

1 SEU is one point end or one signal, simple as that.

There also needs to an allowance for non-SEU (a guess, typically 50% of the SEU count) to cover supplementary detectors, cables, REBs, etc.

Do you have a current realistic market value for an SEU?

 

[Railsigns]

1 SEU is one point end or one signal, simple as that.

Not quite as simple as that. A main signal with an associated PLS counts as 2 SEUs.

Ground frames and plungers each count as one SEU.

There also needs to an allowance for non-SEU (a guess, typically 50% of the SEU count) to cover supplementary detectors, cables, REBs, etc.

The cost of all the items you mention are included within the SEU, so no additional allowance is needed. An SEU also includes design and installation costs.

 

[68000]

SEU would be overkill for your Line of Sight requirements

 

[MarkyT]

SEU would be overkill for your Line of Sight requirements

You'd still need signals and point machines at junctions with a rudimentary interlocking retained, but intermediate headway signals on plain line double track sections would not be required. While full mainline SEU unit rates themselves would probably be overkill for any new facilities, the technique could still be valuable to capture savings in complexity for the plain line sections. It's possible the existing underlying signalling and control ecosystem, if in good condition, could be modified to remove the intermediate signals, and change the aspects displayed to the customary tram type around the junctions, to minimise conversion costs.

 

[DerekC]

Network Rail published a definition of an SEU. I think I have a copy somewhere if it would be useful. However as others have said, the SEU really only works for multiple aspect signalling. Of course you need to work out whether a Line of Sight system would be OK for your LRT, depending on operating speed etc. I recommend a read of the ORR guidance tram systems (you have probably read it already):

http://orr.gov.uk/__data/assets/pdf_file/0018/2637/rspg-2g-trmwys.pdf

 

[Tim M]

The following is based on many years of producing bids for signalling systems. By the time you have developed an SEU equivalent for light rail signalling you could have completed your cost estimate. First you need to lay out your solution (i.e. produce a track plan) using known equipment, e.g. from people such as:

http://www.hanning-kahl.com/en/home.html

You also need to consider the control centre system and depot signalling, the latter can be a significant part of the overall cost. If driver route setting is required, mandatory for street running areas where points must be seen to be clear of little Jenny's feet, that also needs to be added. Oh and don't forget to include any integrations with traffic light systems.

Good luck.