Research in Brief
Procedures for dealing
with bodyside windows
broken in service
T1024
For more information contact:
enquirydesk@rssb.co.uk
November 2015
‘...allowing operational delays to be reduced.’
Aim
There are a number of different approaches used by train operating companies (TOCs) with regards
to bodyside windows broken in service. This research sought to investigate these approaches with the
objective of minimising operational speed reductions and allowing trains to continue to operate with
defective windows in a safe and cost effective way whilst minimising delay.
Findings
The practice of applying an emergency glass repair film is more common for high speed operators
where window breakage is associated more with cold weather and weather events during the winter
months than other causes.
For medium and low speed vehicle fleets window breakage appeared to be more associated with
vandalism.
The windows tested comply with GM/RT2100 ‘Requirements for Rail Vehicle Structures’ issue 5 in
normal and damaged conditions which indicates that there is no increase in risk to passengers if the
outer pane of a window had been damaged.
The research found that there are two conditions to be considered when the outer pane of a double
glazed window is fractured:
•When there is no hole, or a hole less than 85mm diameter, there is no technical reason to fit
emergency window repair film or remove the window.
•When there is a hole greater than an 85mm diameter, it is recommended that either the glass is
removed or emergency window repair film is fitted. Large holes in fractured windows make the
broken pane unstable when subjected to pressure pulses (eg when two trains pass). Emergency
window repair film stabilises the damaged pane.
In deciding to fit emergency window repair film, the TOCs should consider the risks for its operation
of:
•Glass dice from fractured outer panes becoming detached due to further impacts and therefore any
potential consequences due to the effect of train speed.
•Contact or interference at stations by passengers
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When emergency window repair film is fitted to bodyside windows, the procedure contained in
Appendix C of the research project report should be followed. The procedure only requires the film to
be applied to the fractured glass minimising the risk of damage to vehicle paintwork.
If a vehicle’s windows do not comply with GM/RT2100 or with the former BR Standard BR 573, the
window design should be tested to the current standard.
Impacts and benefits
The research has delivered much needed data on the physical performance of train bodyside
windows, both in intact and damaged conditions. It tested and identified suitable emergency window
repair films which will benefit the rail industry. It also delivered a procedure which can be used to
apply emergency window repair film to windows broken in service, both in wet and dry conditions.
This enables better management of broken bodyside windows in service allowing operational delays
to be reduced.
Method
The research project was split into two distinct phases. The objectives of the first phase were to:
•Establish the practices and procedures employed by TOCs for dealing with train bodyside windows
broken in service.
•Identify and evaluate the emergency window repair films that are available to be used by the rail
industry for managing train bodyside windows broken in service.
The second phase of the project was designed to:
•Deliver a testing regime to develop a better understanding of the physical properties of glazed
systems used in bodyside windows of rail vehicles, both when intact and damaged.
•Develop common solutions for bodyside windows broken in service based on a better and quantified
understanding of the properties and limitations of windows.
The research examined data obtained from TOCs to establish the
frequency, and possible causes of, windows broken in service.
This research also tested train windows in both intact and various
degraded conditions. The tests used Mk III carriage bodyside windows as
this represented the fundamental design features found on many other
vehicles. In the various damaged conditions tested, windows were tested
with and without window repair film applied.
Small missile test apparatus
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Where to find out more
Both phases of this research project have now been published RSSB’s web portal SPARK http://www.
sparkrail.org/Pages/Results.aspx?k=T1024&s=All%20Records.
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