Railway Incidents

Question 1

Describe the three main types of electrified railway systems.

Answer 1

Network rail overhead line electrical system (OLE):

• operates at 25Kv AC
• contact wire and retractable pantograph
• do not approach within 3m (ensure current is isolated)

Third rail system:

• operates at 750V DC
• shoes on train pick up current from the conductor rail
• treat as being live at all times

Underground fourth rail system:

• four rails (two running rails and two conducting rails)
• conductor rails electrified to 630V DC
• treat as live until confirmation received that current is isolated and earthed

Question 2

List the main types of incidents on the rail network.

Answer 2

Fire 
Chemical spillages 
Derailments or collisions 
A combination of the above 
Assisting other agencies following suicides.

Question 3

Detail the general precautions to be considered at a railway incident.

Answer 3

• all personnel should wear a high vis jacket at all times. During darkness or poor visibility they should also carry a torch.
• no one to climb above the interior floor level of rail vehicle, unless overhead line are isolated.
• be aware that switching off the electrical supply does not necessarily stop all trains, they may also continue to run on that line.
• all personnel should move to a ‘position of safety’ and acknowledge the audible warning by raising an arm above their head when a train approaches.
• when walking along the track, personnel should walk in the cross and avoid going on or near the line, unless essential.
• avoid crossing within 15m of a stationary vehicle unless certain it will not move.
• if there is no safer alternative, walk in the ‘six foot’ but never in the ‘four foot .
• if caught between adjacent lines on both which a train is approaching, lay face down at a point where the ground is not obstructed, but never in the ‘four foot’.
• crossing the line at track level should be avoided, use bridges, subways or foot crossing points.

Question 4

Detail the component parts of the ‘permanent way. (Refer to diagram)

Answer 4

• the cess
• four foot
• six foot
• ten foot
• conductor rails
• running rails

Question 5

Detail the operational procedures for rescues from overhead line equipment.

Answer 5

• incident commander to request ‘all trains to be stopped and electrical supply isolated’.
• a dynamic risk assessment to be completed before attempting any rescue.
• incident commanders must obtain a ‘permit to work’ to verify that the electrified systems are off, earthed and safe to approach.
• establish a safe system of work.
• use the minimum number of personnel and equipment possible as clearly brief all crew members.

Question 6

Detail the operational procedures for rescues from a conductor rail.

Answer 6

• incident commander to request ‘all trains to be stopped and electrical supply isolated’.
• a dynamic risk assessment to be completed before attempting any rescue.
• incident commanders must obtain a ‘permit to work’ to verify that the electrified systems are off, earthed and safe to approach.
• a visual check to be made to ensure that sort circuiting devices (SCD) are in place
• minimum number of personnel and must be used to attempt the rescue

Question 7

Detail the operational procedures for rescues without implementing all safety procedures.

Answer 7

• ensure the casualty is not in contact with any live electrical equipment.
• immediately attempt to have the train stopped and the electricity supply isolated.
• assess the possible risks against the likelihood of success of any proposed action.
• clearly brief all personnel with regard to their safety.
• personnel must not carry out these rescues when standing on a metal ladder.
• use the minimal number of personnel and equipment possible.

Question 8

State the specific difficulties personnel may have to deal with when performing rescues from trains.

Answer 8

• access to the incident
• unstable carriages
• carriages lying on top of each other creating height difficulties.
• large number of casualties
• evacuation of passengers by train crew

Question 9

Before attacking fires on trains, ensure that:

Answer 9

• on diesel locomotives, the engines have stopped and the battery isolation switch is open.
• on diesel multiple units, the engines have stopped and the heaters are off.
• units operating via OLE, the pantograph has been lowered and the battery isolation switch has been opened.
• on conductor rail systems, conductor rails have been isolated.
• on passenger carriages, that the 1KV electric heating supply is off.
• any catering cars carrying LPG have been isolated.

Question 10

Describe the purpose of automatic train control systems and detail the hazards associated with them.

Answer 10

• commonly used to transmit relevant information to the train automatically.
• acronyms, ATC’s, ETC’s and ERTMs.
• the information is picked up by a eurobalise antenna installed in underfloor of carriage.

Hazard:
- antenna emits electromagnetic energy at a frequency of up to 27,095MHz