Red Alert 28 Safety Briefing

1
Red Alert 28 Safety Briefing

• Understanding the risk from TPWS Reset and
  Continue

February 2007
2
Background

• Between Oct 05 and Jan 07 there were six
  instances of reset and continue following a
  SPAD - bringing the total to 22
• In 16 out of the 22 events the driver knowingly
  reset the TPWS and continued without authority
• Is this an error or violation?
• The SPAD may have been an error but resetting the
  TPWS and proceeding without authority is a
  violation

3
What circumstances lead to TPWS reset and
continue SPADs?

• In the majority of cases the drivers believed
  they had authority to proceed and failed to
  realise a SPAD had occurred before the
  intervention
• Examples of the immediate causes of these
  incidents are
• Drivers not locating the correct signal or
  misreading a signal
• Failure to effectively manage distractions at
  critical times - for example, dealing with faults
  or prioritising on personal matters
• Lack of self discipline by taking shortcuts /
  rushing
• Making assumptions during shunting / degraded
  working conditions having previously operated the
  train stop override

4
Why do drivers reset and continue following a
SPAD?

• Drivers believe the brake application was due to
• A TPWS intervention caused by an over-speed
• A TPWS / AWS fault
• Delay in acknowledging the AWS horn
• Drivers
• Believe that they have had a proceed aspect
• Can see the next signal showing proceed
• Unnecessary brake demands by TPWS/AWS leading to
  complacency and overconfidence in dealing with
  this type of brake application
• Following an unsolicited brake application,
  drivers fail to check the TPWS/AWS brake demand
  light and resetting the brake by other methods
  such as de-energising /re-energising the master
  switch /controller
• Drivers not being aware that after the AWS/TPWS
  button is pressed, the brake demand light will
  reset itself after a short time delay and revert
  to normal in this case the driver failed to
  notice the TPWS/AWS light had been illuminated

5
A point to consider
?

• A train initially receives a TPWS intervention
  and then receives an AWS warning horn. What
  indications would a driver receive in the cab and
  what actions would he or she take?
• Unsolicited brake application
• If noticed - brake demand light flashing
• AWS warning horn received
• Acknowledge AWS warning horn
• Brake demand light becomes permanently
  illuminated until the system times out
• Do you understand the risk and the importance of
  not making assumptions?

6
List 3 examples of hazards/risks and potential
consequences of Reset and Continue following a
SPAD

• Although the driver believes a SPAD has not
  occurred, after the resetting of the TPWS, the
  train may be heading towards a conflict point and
  a possible collision with another train
• The driver is overriding a critical safety device
  that is designed to protect the train
• This is a serious violation of rules and could
  result in formal discipline and, in the most
  serious of cases, prosecution

7
The signal ahead may be showing proceed but
does it apply to you? What should you do?
Points!
8
After a TPWS intervention when you are aware
that a SPAD has occurred

• Under no circumstances may the train be moved
  without the signallers authority
• This has occurred in at least two of the
  incidents as the drivers involved perceived it
  was safe to move the train to either save time in
  contacting the signaller or to move to what the
  driver perceived as being a safer location
• But this was wrong - with the exception of a TPWS
  brake intervention on approaching buffer stops,
  in all other instances when the TPWS has stopped
  a train, the train must not be moved without
  first obtaining the signallers authority
• There are no other exceptions!

9
Whats the industry doing to improve the system
and design of cab equipment?

• Work is ongoing to
• Pursue the removal of the regulated requirement
  to fit TPWS in respect of permanent speed
  restrictions where TPWS does not deliver a safety
  benefit
• Optimising the equipment to reduce the number of
  unnecessary brake demands at PSRs and
  buffer-stops (this should minimise the number of
  brake demands which drivers perceive as being
  unnecessary)
• Evaluating proposed modifications to improve the
  driver interface and reduce the likelihood of a
  driver mistaking a TPWS brake demand for an AWS
  brake demand

10
Remember

• Unsolicited brake application always check the
  TPWS/AWS brake demand light first
• Never take a chance by resetting and continuing
  without the correct authority - irrespective of
  the circumstances
• Even if you are certain that a brake application
  was caused by the AWS, you still have to obtain
  the signallers authority before proceeding

?
11
Think before you reset

• Brake application not initiated by the driver
• Check the TPWS/AWS brake demand light first
• If flashing, acknowledge the brake demand light
  by depressing and releasing the TPWS/AWS button
  on the drivers desk
• Ensure the train is brought to a stand
• Immediately tell the signaller what has happened
  (except when approaching buffer stops)
• Carry out the instructions given by the Signaller
• Do not move the train until the signaller has
  given you the authority to proceed

12
Red Alert 28 Safety Briefing

• Understanding the risk from TPWS Reset and
  Continue

February 2007