London Underground uses RFID technology to support their escalator maintenance operations and worked with CoreRFID, specialists in RFID applications and technology, to develop a solution for London Underground. Guest Blog by CoreRFID Ltd.
CoreRFID developed the London Underground Step Tracking System.
The escalators of the London Underground carry over 3 million
passengers every day from the street to the platforms and back
again. Most commuters and tourists don't give the travelling metal
staircases a second thought; a fact that is a testament to the
reliability of the system and the care taken over the maintenance
One part of London Underground is responsible for maintenance,
upgrading and replacement works across two thirds of the London
Underground system, and has almost 200 escalators to support.
Maintaining escalators is a task with unique problems. Failure
to carry out adequate preventative maintenance puts passenger
safety at risk but taking escalators out-of-service during normal
travelling hours is unpopular with passengers as well.
To address this London Underground decided to use RFID
technology to support their escalator maintenance operations and
worked with CoreRFID, specialists in RFID applications and
technology, to develop a solution for London Underground.
The result, the Step Tracking System, combines readily available
components in an innovative way that promotes passenger safety and
convenience for London Underground and saves costs in service
engineering. CoreRFID developed a pilot version of the Step
Tracking System as part of a joint project with London Underground
and is now involved in its operational deployment across the
Bakerloo, Central, Victoria, Waterloo & City, Metropolitan,
District, Circle and Hammersmith & City lines.
THE BUSINESS PROBLEM
Failures could put passengers at risk. Millions of passengers
use the escalators on the London Underground every day. The steps
that make up these escalators are subject to constant wear from the
feet of passengers and from the mechanical movement on the
escalator track. A failure in an escalator step could cause serious
injury. If an escalator step were to fail during the rush hour,
lives could be put at risk and serious disruption to travellers
To prevent such an event, London Underground has an inspection
and maintenance regime that ensures the structural integrity of
every step is checked at least once during the course of every
With almost 30,000 separate escalator steps needing to be
checked this maintenance approach requires significant effort by
London Underground's engineering staff.
The problem is complicated by the time required to carry out
non-destructive tests on the structural integrity of steps. Because
of the effort involved, only a small number of steps can be removed
from the escalator to be tested during an over night maintenance
shift. These steps are exchanged for already tested ones. The
removed steps are transferred to another site for testing before
returning to the pool of steps available for re-installation. The
issue of step control is complicated by the fact that there are
many types of escalator, although almost 70% of all steps belong to
one of the four main types. As a result any one escalator consists
of an ever changing set of steps. Keeping track of when each step
was tested and replaced is a major challenge. On some occasions
steps are removed from escalators simply in order to identify
In addition, although individual steps are identified by a plate
on each it has proved difficult to link the identity of a step with
its engineering history and that if a step should fail a test it is
almost impossible to know whether there are other steps in the
network that have the same usage and service history that might
also be at risk of failure. Difficulties with the readability of
plates (they become obscured by dust and grease) and the problem of
having to stop escalators in order to read step data means that
information can only be collected during the over night maintenance
shift and even then information is rarely completely accurate.
London Underground needed a system that would collect data
automatically from individual steps, that could cope with the
problems of dirt and grease and that would be robust enough to
stand up to the constraints of one of the world's most heavily used
mass-transit systems. They turned to RFID as a technology to help
The Pilot & The
CoreRFID and London Underground worked together to come up with
an effective solution design and to select and trial the most
appropriate technology in a pilot application.
The eventual solution was to attach UHF RFID tags to the
underside of each escalator step. Whenever a check is needed of the
specific steps present on an escalator, the tags can be read by a
portable reader that is slotted into a cradle near the track of the
escalator mechanism on a regular basis,. As the escalator runs and
each step passes the cradle, the reader detects the signals from
the tag. In this way information about which steps are present in
which escalator can be collected without interfering with the
normal operation of the escalator.
RFID tags installed under steps need to be able to cope with
vibration, grease and dirt as well as magnetic and electrical
The tags used were designed to be usable in the difficult
environment of an operating escalator with vibration, temperature
variation and magnetic fields all being a factor.
A decision had been taken longer term to mount the tags on the
steps using rivets but for an initial trial mounting the tags by
using acrylic adhesive was tried. In practice the adhesive mounting
for tags proved more robust than anticipated. In spite of the
vibration, dirt and constant movement, not a single tag detached
from its escalator step over a period of two months. Even so,
riveting is being used for the eventual deployment to ensure
that tags remain attached.
The initial trial was conducted on an escalator at St Paul's
underground station on the Central Line. Tags were installed on the
92 steps of the escalator and data written to each tag indicating
the step number, its year of manufacture and elements of its
The writing process was monitored carefully during the trial. It
was recognised that initial data recording would need to be done
while the escalator was out of service and that, as a result, the
time taken for each step had to be kept to a minimum. Writing data
to RFID tags is very much slower than reading and requires the
writer to be significantly closer to the tag than does reading. For
the Step Tracking System, the escalator is inched forward, a small
number of steps at a time, as the data is recorded on each step.
London Underground expect that, in time, they will be able to
achieve a time of 45 minutes for a 90 step escalator, allowing the
writing process to be accommodated during a normal out-of-service
shift. Data is being held on the date of the last non-destructive
test (NDT). Because of this it will be possible to check that any
given step has not exceeded the time allowed between NDT's, helping
to avoid the risk of failure. This will help to protect passengers
and reduce disruption to escalator services.
CoreRFID worked with London Underground to devise a way of
packing the data to be recorded on the tag. UHF tags typically hold
as little as 64bytes of data. By minimising the amount of data to
be read, London Underground and CoreRFID expected to be able to
ensure that high read speeds would be possible.In practice this was
found to be the case. With the reader mounted in its cradle, it was
possible to retrieve data from the steps as the escalator ran at
its normal speed. Trials indicated that it was possible to
consistently and accurately read the data from the steps during one
or at most two rotations of the escalator.
COLLECTION & USE
The Step Tracking System uses a reader / writer integrated with
a rugged handheld computer, suitable for use in the dusty and
greasy environments found under escalators.
The reader/ writer can be operated with one hand and has a
battery life of between four and fourteen hours of continuous use,
allowing it to be used for an entire shift without re-charging.
The application running on the hand-held computer has been
designed to be simple to operate when used in the cramped
conditions found in the escalator well. The same application is
used by the manufactures of steps to encode manufacturing details
on each step before new steps are delivered.Data stored on the tag
and, as a result, available for collection includes the unique step
identifier, manufacturer, date of manufacture, station, escalator
number, step number on the escalator, and so forth. Reading the
data provides the basic information needed to manage each
individual escalator step. For the first time it will be possible
to know exactly how long an individual step will have been
installed on an operational escalator. It will become possible to
make better decisions on when steps need to be exchanged for
testing or replaced.
Data collected in the Step Tracking Systems' hand-held computer
can be extracted in a simple data exchange format such as XML or as
comma separated value (CSV) file. It can then be integrated with an
asset database system such as Mincom's Ellipse.
The Current Status
By March 2009, only two months after the commencement of the
project, tags had already been installed on four escalators.
London Underground and CoreRFID had also agreed a schedule for
progressive implementation involving the installation of 1400 steps
for the ten escalators at Kings Cross underground station before
the end of July 2009. CoreRFID will also be training of two of
London Underground's suppliers to deal with a further 2000 steps
across seven underground stations and a further 2700 steps on 13
escalators by London Underground themselves.
Early installation experiences indicate that applying tags to
new escalators and steps is relatively straight forward. Tags will
be riveted in place as part of the manufacturing process. Adding
tags to existing steps in situ has difficulties as predicted by the
experiences in the trial. This is mainly related to identifying the
steps in situ where, grease, dirt and poor lighting hamper the
process and introduce the risk of error. However, cross checking
data between what is expected and what is found is seen as being
the best way to reduce the risk of error.
To date (November 2011) over 20,000 steps have been tagged; some
in situ and others as part of the step manufacturing process by
London Underground's suppliers Otis and MDS.
Advantages of the Step Tracking
The Step Tracking System created by London Underground and
CoreRFID has a number of advantages over manual and other automated
or semi-automated systems.
The most important of these are:
- Automated system provides data without interrupting
- Data on step usage allows better prediction of
- Automatic collection of data eliminates manual errors
from data collection.
- Improved visibility of wear gives better passenger
- Approach means only one engineer needed to collect step
data. (50% saving)
- Hand-held computer provides low-cost and easy to use
- Combined with portable ultrasonic flaw detection, can
avoid the need to remove steps for testing.
- Hand-held computer software is simple to use for
- Data captured can be integrated with existing asset
Technical Data The Step Tracking
System comprises four main components:
- Hand-held, reader-writer computer
- Step Tracking Systems application
- Passive RFID tag
- Tag data code and formats
THE NORDIC ID PL3000 MOBILE COMPUTER
The mobile computer used in the London Underground
application is the Nordic ID PL3000. The Nordic ID PL3000 is a
robust, high performance, high reliability mobile computer which
incorporates an integrated RFID reader-writer for UHF chips (it can
also have a barcode reader or 2-D barcode reader built in as well).
The Nordic ID PL3000 runs the Windows CE operating system. This
system weighs about 500g with its battery which provides up to 14
hours operation. The user interface is via a 3.5 inch quarter VGA
touch screen and a 29 key keyboard. Each of the keys on the
PL3000's keyboard can be back-lit under program control in order to
direct the operator. PL3000 has been designed for one handed
operation. The PL3000 can be equipped with a range of communication
- WLAN connection for wi-fi link for data
Step Tracking Software
The Step Tracking application software running on the Nordic ID
PL3000 has been developed for the Windows CE operating system. The
application includes the following main modules:
- User set-up
- Step data down load (receive)
- Step data record (write)
- Escalator scan (read)
- Single step scan (read)
- Step data up-load (transmit)
Passive RFID Tag
The passive RFID tag used in the London Underground application
is the Confidex Ironside G2XM UHF tag. This tag was selected
because of its robustness, read reliability, and its suitability
for on-metal mounting with either adhesives or pop rivets. The
Confidex Ironside conforms to EPC Gen2 protocol standards and
provides a user-writeable area of 512 bits. It has a read range of
up to 8 metres and meets the IP 63 (IEC60529) standard which
defines a dust tight and water tight enclosure. The Ironside tag
has a temperature operating range of -200 C to + 650 C.
Because of the limited data storage area on the tag, CoreRFID
developed a compact data storage format for the Step Tracking
System which succeeds in packing the necessary application data
into only 43 bytes.
Data held on the tag for the London Underground implementation
- Step Type*
- Year of Manufacture*
- Part Number*
- Escalator Number+
- Step Position+
- Step ID Number*
- Date of Installation
+ *Items are written when the step is first delivered.
+ Items are written when the step is installed.
About CoreRFID Ltd.
CoreRFID works with over 1500 customers across the UK, Europe,
the USA and the rest of the world, providing them with the
technology, systems and support they need for their
applications.Users of CoreRFID solutions are found in finance,
broadcasting, construction, defence, government and
telecommunications. Customers include the Ainscough Cranes, BBC,
Capita, Nokia, BAA, Thames Water, the Channel Tunnel, Norwich
Union, Costain, Survitec, British Aerospace and many others.
CoreRFID specialises in the complete range of technologies for
track, trace, audit and control applications, especially in
transport, safety and manufacturing, assisting customers in making
the right choices for business critical applications.
CoreRFID provides customers with:
- RFID tags, sourced worldwide or custom
- Tag reader / scanner devices
- Mobile computers for tag reading / scanning /
- Design, development, implementation and support for RFID
- Training and implementation service.
CoreRFID was formed in July 2007 the management team
successfully completed a management buyout from Mannings UK to
create a business exclusively focused on the needs of RFID
technology users and with over 15 years of RFID experience.
CoreRFID retains all the staff, know-how and intellectual property
of the Mannings RFID business. The CoreRFID team of experienced
engineers and its sales and administration centre is based in
Warrington, in the North West of England. CoreRFID is backed
by Enterprise Ventures and NatWest Bank.
© Core RFID Ltd 2011CoreRFID Ltd. Dallam Court, Dallam Lane,
Warrington, WA2 7LT T: +44 (0)845 071 0985 F: +44
(0)845 071 0989 E: email@example.com W: www.CoreRFID.com
The London Underground case has also been presented on the 2010 issue of the Nordic IDea.