SATS and Bats
On 28th September 2001, London Underground
issued a press release describing a new platform attendance scheme. The idea
was to help get trains away from stations more quickly by using additional platform
attendants with batons and microphones. Much newsgroup correspondence has been
generated by this scheme so Tubeprune thought it would be worth offering some comments
LU's Original Press Release on SATS and Bats
"London Underground is launching a new scheme for
Central Line users on Monday (October 1 2001) to concentrate on saving valuable seconds
when trains are waiting to leave stations.
"Extra platform staff will be located at key Central
line stations at Bank, Bond Street, Liverpool Street, Chancery Lane, Holborn, Oxford
Circus, Tottenham Court Road, Mile End and St. Paul's. By using new
"batons" (a signalling device shaped like a table tennis bat) and mobile
microphones, along with special training, these new staff will focus on safely ensuring
trains are not delayed by customers holding doors and causing danger to themselves by
rushing to board at the last second.
"London Underground's Customer Services Director, Mike
Brown said: "We want to make customers' journeys as quick and easy as possible.
Trials have shown that if we can help people get on and off our trains quickly and safely
we can significantly reduce the time trains spend in stations and speed up overall journey
"The initiative will be introduced on our busiest
platforms right across the network over the coming months. Northern line customers
will be the next to see the benefits with the launch scheduled for six weeks time."
Well, that's what LU said. How does it work in
practice? The following paragraphs offer some insight.
The original LU
press release is here
What are SATS?
This is the acronym used by London Underground to refer to
the station staff who are posted on platforms to assist with getting trains away
quickly. SATS are "Station Assistants, Train Services".
What are the Bats for?
These are the batons used by the SATS to signal to the driver
that he can close the train doors any time now. They originated in Germany and have
spread to other countries over the years. They consist of a white disc on a stick,
which is held up by platform staff to indicate it is time for the train to depart.
>Kat< (who works on an Underground station) put it like this in uk.transport.london,
"The whole point of the white baton is that it's an indication that the SA thinks
it's safe for the driver to shut the doors and go. It is not a direct order.
The ultimate responsibility remains with the driver."
Why do they need SATS and Bats?
The whole point of a metro service like the London
Underground is to keep the system moving. Trains should only stop at stations long
enough to unload and load. If trains are running at two-minute intervals (120
seconds headway as it's called), 40 seconds is the longest they should stop at any
station, less if possible. This stop time is called the dwell time. At the
worst stations, dwells often exceed this 40 seconds in peak times and the SATS with their
bats are there to help get the dwells down to 40 seconds or less.
Are doors open for 40 seconds?
The 40 seconds dwell time isn't just the time the doors are
open, it's the whole time the train is standing still from the wheels stopping to them
starting again. In the 40 seconds you have to include time for the driver to make
sure the brake is on to hold the train still, press the open doors buttons and for the
doors to open. This is 5-6 seconds. Then there is the same time for closing
doors and restarting the train. This is another 5-6 seconds. That means the
time available to passengers for getting on and off is less than 30 seconds. At Victoria
these days, it sometimes goes up to 60 seconds.
Why does a few seconds matter?
If a train loses just 3 seconds at each station, after 40
stations, it will be running 120 seconds late. If there is a train every two
minutes, our late train will be soon running in the path of the train behind.
Since it is now running late, the number of people waiting for it at each station will get
bigger and it will then get more late while more of them get on and off.
Haven't you noticed how a late train waits longer and longer at each station?
Soon, a queue of trains will develop behind the late running one and
then the whole line is running late. Yes, a few seconds really does matter.
There was a suggestion that the bats were to be used to push
passengers onto trains. Oh, no, come on, not in this politically correct age.
A London Underground spokeswoman said: "The batons will not be used to hit
passengers. Staff will not touch or shove passengers in any way." Hey,
they're too afraid of being sued for assault to do that.
What do the drivers think?
"romic" writing on u.t.l offered the
The driver can see the baton as the train leaves the platform
on the monitor inside the cab [on some lines which have in-cab CCTV]. The idea is that he
then stops the train if the baton is lowered (?) before the monitor cuts out as the last
car leaves the platform. In the past, the driver would give cursory glances to the monitor
as the train leaves the platform, dividing his time between the monitor and the road
ahead. Now this means that the driver is now spending even more time concentrating on the
monitor rather than watching the road ahead. This leads to the potential risk of a
SPAD etc. if the train is being driven manually, such as on the Jubilee or Northern Line.
Of course, this was wrong. In reality, the SATS would
hold up both arms, one holding the bat, one not and wave them over the head to attract the
driver's attention to an emergency. On the ATO lines (Central and Victoria) they
also have emergency stop plungers on the platforms and this is a more effective way of
stopping a train in an emergency.
"romic" continued: Most
drivers query the wisdom of SATS and see it as just another waste of time/money. A
SAT with raised baton doesn't officially give the "right" to a driver to go, it
is still up to the driver to decide when to close the doors and depart and to observe the
platform, just as it always has been. In the end, if anything happens, it is the
Tubeprune thinks that if drivers understood what SATS were
for, they wouldn't think it a waste of time and money. LU should have explained it
Why all this fuss now?
Actually, this stuff with SATS isn't new. It was
standard practice for all LU stations to have staff assisting with getting trains away
quickly during rush hours. Even the country stations used to do it. It
was called giving the train staff the "right away". They just didn't have
bats then. The bats idea originally came from the main line railways in Germany,
where bats were commonplace. You see them on some British main line stations where
platform staff assist trains staff to get away on time.
In the past, passengers on the Underground were used to being
encouraged to get on and off trains as quickly as possible. They knew there was a
need to hustle. They became educated by the actions of the platform staff to behave
in a way to help keep the trains running.
Over the years, the annual fall in passengers of 0.5% to 1%
from 1947 up to the mid 1980s actually reduced the rush hour crush. There wasn't so
much need for hustle by then, even at peak times. Platform attendance was reduced
and almost disappeared. Now the story is different. The number of passengers
travelling has doubled since 1983 but, in the meantime, LU lost all its expertise in
handling large numbers of people. Now they are having to re-learn how to cope and
passengers are going to have to re-learn how the hustle along at peak times. This
SATS and bats idea is a good way to do it. Recent improvements in performance
suggest that the scheme is working. It does need to be extended and it must be kept
up. Some stations need it all day.