Hi

can anyone clarify the exemptions oulined in the 17th edition regs regarding railway applications, specifically clause 110.2 (ii).

This clause states that "RaiIway traction equipment, rolling stock and signalling equipment" are exempt.

Traction and rolling stock is fairly obvious, we're talking 25kV OHLE and on board power for example.

When it refers to Signalling equipment does this include lineside power distribution (650v, 400v, or 230v)which forms an intergral part of any modern system?

Network Rail standards states the advocation of BS7671 where practicable for signalling power feeders and mention is made of the above clause in the regs, however it does not appear to be mandatory.

Can anyone help define exactly what "Signalling Equipment" in the regs actually means?

many thanks


Mike

Hello Mike,

One of our old members is the God of railway electrics and a dear friend. I'm not sure he is allowed to use forums from his elevated position, perhaps too busy because of the pressure, but I'll send him a text about your post after the weekend.

Give it until next week and you'll have the definitive answer, I'll reply by proxy if he agrees to help and if appropriate.

Zs

To the best of my knowledge, railway signalling equipment is related to equipment controlling and managing train operations directly, that is not related to Traction Power.

So "Automatic Train Control", "Moving Block Processors" etc. are all part of "signalling equipment", but SCADA for traction power, HVAC at a station, passenger information displays on the platform, etc., are not.

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Eur Ing Graham Kenyon CEng MIET

In a past life I always found the old H M Railway Inspectorate very helpful on all manner of technical enquiries about railway safety. That was when it was part of HSE, now they have merged with the Office of Rail Regulation I cannot comment on the current state of helpfulness.

May be worth a call to ORR on 020 7282 2000 as the London office - plenty of other numbers for their regional offices on the ORR website.

Or wait for the oracle via Zs.

Ok

to go one further, how do organisations such as UKPN comply with the regs?

Example, what if they run a 400v feeder from one substation to another, are they required to comply with the regs or is there a different set of standards for them?

You'll forgive me if my question sounds a bit ignorant, but this is not my industry/job and I'm curious.

thanks

Mike

Here you go Mike, in haste cos I'm running late for dinner but I have a reply for you from he who must be obeyed when it comes to things rail. He looked at your post;

'7671 Does not apply to the trackside signalling supplies but NR expects the installation to comply as if it did as far as possible. Most signalling supplies are IT (not referenced to earth). However the incoming DNO and primary distribution up to the signalling system is usually 400 Volt 3 phase and that part of the installation must comply with 7671.'

What a great resource this forum is. Someone who knows someone...

I hope that helps,

Zs

Mike Pears
At the start of the regs book there is a section that states where the regs apply and where they are exempt. The regs themself specificaly exempt themselfs from public distribution systems.

Mike,

The Regs have an exemption for Railway Signalling Supplies, however that applies only to "Signalling Circuits".

As a general rule, Signalling Circuits are 110Vac and below. You should have identified a demarcation point between Signalling and Power circuits (usually the 650:110V transformers).

In short, Lineside Power Distribution, 650V IT, 400/230V TN should always be designed to BS7671.

PM me if you need any more info.

Regards,

Iain