The effects of weather on railway operation

     The following is a summary of papers given at the event for interested parties.

     Notes from the following presentations are reproduced here:
 

• passenger numbers and rolling stock are affected by the weather
• daily income from passenger ticket and freight sales is approximately £10,000,000 - if no services operate, this amount is lost to the operators
• the weather, particularly storms and frosts, affects leaf fall rates
• total delays on the Railtrack network amount to 25,000,000 minutes a year
• general weather effects
• low temperatures
• snow and ice
• engine and power failures
• blocked and slippery track
• high temperatures
• track buckling
• speed restrictions
• lineside fires
• high winds
• overhead cables can be damaged
• leaves blown on the line (costing £10 million a year to clear)
• tree felling
• heavy rain
• track flooding
• landslides
• thunderstorms and electrical disturbances to signalling
• fog
• delays caused by shorter sight lines
• speed limits imposed
• Has rail become more weather sensitive?
• steam trains used to burn off lineside vegetation
• modern disc brakes don't remove leaves, unlike older clamp brakes
• modern trains are lighter and more badly affected by slippery conditions
• overhead cables are vulnerable to the wind
• diesel engines are vulnerable to dry snow intake and diesel waxing (at -18 deg. C)
• electric trains are vulnerable to ice causing conduction problems
• Is Continuously Welded Rail (CWR) more likely to buckle?

     Mr. Brownhill explained his company's weather forecasting systems for the rail network. These divide the country into 22 regions (based on rail operating areas and general climatic conditions, for example to Severn Estuary in Wales and England is deemed to have similar characteristics, but different from, say the southern West Country). The forecasts are given for snow, conductor rail icing (Southern DC lines only), high wind and temperatures based on thresholds of 0 and 36 degrees C. The forecasts are 24 hours in advance and given in yes/no format, ie will the event occur or not. There was some debate as to the reliability of this forecasting regime.

• Integrated control and monitoring systems are being introduced onto the network, aimed at avoiding delay and improving service

• These include switch (point) heating, wind detection, backup generators and ice detection
• The Icelert unit measures rail temperature, air temperature, rain and snow
• limitations of the equipment
• heather maintenance and verification (ie does the heater work?), possibly required in all conditions
• monitoring systems
• remote routine maintenance by computer
• integrated monitoring units
• points mechanisms located in more accessible places

• in 1998/1999, 6,000 hours of delay were due to weather (up 44% from previous year), and 4,500 hours of delay were due to poor adhesion (up 58% from previous year)
• Railtrack are deemed responsible for weather related delays, and these are determined through TRUST reports.
• general weather effects
• flooding undermines ballast and causes track instability
• wind causes overhead line damage, falling trees and higher waves on coastal lines
• snow can drift and affect visibility
• cold weather can cause freezing of points and broken rails
• heat can cause
• signalling failures
• rail bucking (caused by extreme temperature variability)
• drying out of track formations, especially in clay areas
• landslips after flooding
• increases in trespass and vandalism
• Railtrack's flood prevention guidelines
• identification of high risk sites
• rigorous assessment of new developments
• management of maintenance contractors to prevent blocked drains
• weather reports and telemetry
• sharing information with the Meteorological Office and Environment Agency as well as liaison with local authorities
• remote monitoring of pumps (again to see if they are working)
• working with the National Farmers Union to ensure ploughing is done parallel to railway lines
• wind effects
• level crossing barriers can be blown
• flying debris can be brought onto the track and in front of trains
• mitigation
• anenometers (monitoring)
• studies into the relationship between wind and overhead line equipment
• vegetation clearance to minimise the effects of falling trees
• snow
• drifting
• visibility, particularly for old signalling (semaphore, non AWS?)
• dry snow entering traction motors
• mitigation
• snow ploughs and icebreaker rings for tunnels
• snow type prediction and drift forecasts
• point heaters, fitted to 80% of points
• heat
• mitigation
• preparedness programme in case of track buckles
• rail stressing and ballast strengthening to stop lateral movements
• air conditioning of signalling equipment, which generates a lot of heat itself, to stop it from overheating
• Operation Scarecrow against vandalism and trespass
• adhesion
• slipping and sliding
• failure of signalling equipment if leaf fall insulates track circuits
• humidity can also affect adhesion levels
• mitigation
• tree felling of problematic species, a last resort, especially where birds are nesting
• sandite and water jets, on train sanders
• leaf fences, nets and shrubbery with sharp leaves to catch falling leaves
• improving driving techniques
• adhesion monitoring
• maintenance vehicles
• Railtrack weather group
• national champion
• zonal groups and champions
• sharing of best practice
• toolkit of ideas
• innovation
• adhesion working group (separate)
• weather sensitivity analysis of delays v. weather

• weather impacts on the business include
• passenger income
• the customer interface (eg stations)
• rolling stock
• the weather is an opportunity as well as a threat
• income
• positive and negative effects
• costs of mitigation
• performance regime costs
• punctuality
• cancellations
• short formations
• benefits of "good" weather (not too hot or cold)
• reliability (the best periods are from March to May)
• income generation
• performance regime benefits (though these are cyclical)
• lower costs in staff and trains (eg less sickness and failure)
• extreme weather
• income
• positive if hot
• negative if cold (in general)
• performance regime costs (season ticket discounts etc.)
• mitigation
• costs of repairs and recovery (insured)
• very hot weather
• traction packages may be affected
• air conditioning stressed
• effects on staff (failing to turn up for work)
• leaf fall
• damage to wheelsets (wheelspin and wheel flats)
• cost of loss of vehicle for repair
• burning out of electrical equipment
• very cold weather
• public area precautions
• salting
• effects of rock salt
• track circuit failures
• metal (inc. track) corrosion
• rolling stock precautions
• removing water from toilets
• train exterior cleanliness
• failure of train washers and having to clean units by hand
• snow ingress (dry powdered snow) into traction motors
• conductor rail icing
• burnouts of resistor grids on units caused by poor conduction
• staff costs
• mitigation
• design, especially of trains
• frost and snow proofing
• traction motors
• door design
• lagging of toilet tanks
• sanding equipment
• wheel slide protection
• proper contingency plans
• accurate forecast information
• revisions to train services (made possible by accurate forecasting)
• call out arrangements
• preparing for the worst, for example ordering spare wheelsets in advance of leaf fall causing wheel flats
• industry wide cooperation
• provision of sandite and deicing services to Railtrack (which CSC does)
• running "ghost" trains
• inter TOC contingency plans
• the weather is a major business driver for TOCs both in terms of revenue and cost terms

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written up by A.Boodoo, 24-May-99, © A.Boodoo, 10-May-04, r1.2