Modern Railways – April 2019

41

Pan Up

http://www.modern-railways.com April 2019 Modern Railways

for safety but performance is

just what you moan at others

about, why accept any risk?

THE LOSSES

It wasn’t only safety which Network

Rail was interested in, but the losses

in the system. An unintended

consequence of the pointless drive

to fit all trains with electricity meters

was that people realised that there

were losses in the system. This might

have been apparent anyway, as if

you shove thousands of amps down

a lump of steel it warms up – that

is the losses. It happens in a copper

wire too, but much less because

higher voltage means less current for

a given power. Power is the voltage

and current multiplied together,

but the losses are proportional to

the square of the current, which

is where the problem lies.

Now while these losses were

hidden in the overall electricity bill

nobody cared, but now the train

operators had worked out they

were paying for power that never

made it to the train, they started

getting uppity about it. Network Rail

argued that there wouldn’t be any

losses if there wasn’t a train pulling

current, but in the end they ended

up with the losses on their bill.

While this is bearable on the

25kV, it is quite a bill on the third rail,

where losses can, in the extreme,

get up to 20%. This is because

the system was designed around

four-car wooden bodied units with

a 1,000hp power car, but was now

being used by ‘power hungry lard

butts’ as my colleague Mr Ford

called them. I would of course say

they are crashworthy designs with

performance to enhance the railway

of the future. Short of laying fancy

conductor rails that are expensive

and very attractive to scrap metal

collectors, all you can do to correct

this is add more substations,

but more on this story later.

THE FALL

Of course we now know that 25kV

electrification is not as easy as the

video made it look. It ended up four

times the price it should have been

and got cancelled. We are now left in

a fantasy world where money goes

into looking for alternative power

sources nowhere near as efficient as

even a third rail. The case for third rail

conversion vanished like a metallised

balloon on a 25kV overhead. Even

if costs are controlled, the best

we can hope for is double the BR

figure – so the balloon is still burst.

SAFETY FIRST

The ORR edict states that there

are six times as many casualties

on the third rail than on the 25kV

system, which sounds pretty bad.

So let’s have a look at the statistics.

In the RSSB’s safety report for

2016-17 there is an accidental risk

profile, split between passengers,

workforce and public using ‘Fatalities

and Weighted Injuries’ (FWI) data.

In brief this means a fatality counts

as one, the same as 10 major

injuries, 200–1,000 minor injuries

(depending how serious they are)

and the same for shock/trauma.

So if 1,000 people cut themselves

on a raised screw head (and report

it) that is the same as a fatality.

I’m not mocking it, if you just

use fatalities there isn’t enough

data – this isn’t the road network.

Returning to 2016-17, electrocution

only shows up in the ‘workforce’

section, and even then scoring

0.5 FWI. For comparison, slips, trips

and falls in the workforce scores

10.1 FWI, while for passengers it scores

27.2. In the whole graph electrocution

is the smallest figure, although

trespass scores 33.5 (mainly suicides).

Going back a few years I can find

one unfortunate carriage cleaner

who was killed in a depot and

two passengers who fell from the

platform onto the live rail. In both

of these latter cases ‘alcohol was a

factor’, as it says in reports. Just to

be clear, I am not making light of

any injuries: they shouldn’t happen,

and if everyone does as they should,

they won’t. But we don’t live in a

perfect world – especially after dark.

MITIGATION – DEPOTS

To mitigate the risks we could modify

the edict to say ‘no additional third

rail depots’, which is easy because

we don’t need any to infill the

last Southern lines and perhaps

modestly extend the network.

MITIGATION – PUBLIC ACCESS

Stations and crossing areas are

the next risk area, and there is no

technical reason why these have to

remain live when there is no train

in them. The Bordeaux tram system

uses a ground pick-up system that is

only live when there is a tram on it.

The instant it has gone, people tread

on the contacts in complete safety.

For the main line railway,

people shouldn’t be there. But if

someone falls on the track as a

train approaches, their situation

is pretty bad anyway: the state of

the live rail is not really relevant.

I therefore suggest new third rail

stations are fitted with this ‘dead

rail’ technology, which I would

define as ‘only live when a train is

in section and for a maximum of

300 metres length ahead or behind

the train’. That would close out all of

the risks based on available data.

Also worth a mention is the

yellow line on the platform.

Originally this was to stand behind

when high-speed trains passed

the platform, but it seems to have

been promoted so that now to

step over it is to enter the death

zone, even if every train stops at the

platform. Staff are trained to yell

like gym teachers if you put a toe

over it, third rail or no third rail.

MITIGATION – TRESPASS

Trespass is a big problem with or

without the live rail, and the practice

of slowing or even stopping trains

when trespassers are sighted creates

a business case for the heavy-duty

fencing now seen around railways

anywhere near habitation. This

fencing closes out the electrocution

risks to trespassers. The policy should

just say that the railway should

‘be fenced to current standards’.

Occasionally track workers have

to go on the ‘live’ railway, but this is

Diesel island: Turbostar at Crowborough on the Uckfield branch on 10 May 2018. In his 2017 report on the

Southern network, Chris Gibb suggested 25kV wiring and dual-voltage units for this line. David Andrews

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