IEC TR 62267-2:2011 pdf – Railway applications – Automated urban guided transport(AUGT) -Safety requirements – Part 2: Hazard analysis at top system level.
5.8 Reference to IEC 62267
The column “lEG 62267:2009 provides the references to the safety requirements described In Clause 8 of lEG 62267:2009 which might be considered for choosing safeguards or appropriate combinations of safeguards and to establish their system requirements as requested by lifecycle phase 4, described in 6.4 of of lEG 62278:2002.
The entry “Out of scope” is provided If a hazardous situation and the assigned safeguard are not specific to AUGT systems because in conventional operahons operational staff on board trains Is not Involved in hazard mitigation. Thus. “Out of scope” is entered in the column when no reference to a safeguard is provided in IEC 62267.
6 Structure of hazard analysis table
6.1 General
The present hazard analysis table Table 1) is structured according to the basic functions of train operations for which a driver from the front cabin or attendant staff on board the train has a responsibility for ensuring safe operation depending on the grade of sutomation. Each basic function is intended to cover their associated top-level hazards as described below.
6.2 Hazards associated with “ensuring safe movement of trains”
Ensuring safe movement of trains and its associated basic functions “ensure safe route”. “ensure safe separation of trains” and ensure safe speed” Is intended to cover all hazards leading to derailment or collision of trains with other trains or Infrastructure caused by
• unsafe routes and route elements (e.g. moving points, flank movements or oncoming train movements),
• insufficient spacing between trains and between train and infrastructure (e.g. line end),
• exceeding permitted speed (e.g. due to wrong determination. or wrong adherence).
Due to the fact that “safe movement of trains” has to be considered, at least from Semi Automated Train Operation (STO) onwards, as never being under the responsibility of operations staff on board trains and as being realised as state of the an by technical train control and protection systems. it was decided to declare these basic functions as not AUGT specific, However, safe movement of trains and coverage of associated hazards is the most important prerequisite for any AUGT system as stated by IEC 62267:2009,
63 Hazards associated with “drIving”’
“Driving” represented by the basic function “control acceleration and braking” shall be considered as not being under the responsibility of operations staff on board trains at least from Semi Automated Train Operation (STO) onwards.
Automation of acceleration and braking Is realised as state of the art by technical systems. Therefore it was decided to declare these basic functions as not AUGT specific, taking into account that the associated hazards caused by insufficient acceleration and braking are covered by the basic function “ensure safe speed”.
6.4 Hazards associated with “supervising guideway”
In grades of automation DTO and UTO. the responsibility of on board staff for supervising the guideway in order to prevent as f at as possible collisions with unmeant obstacles or persons in the guideway has to be mitigated sufficiently because operations staff is absent from the front cabin of the train,
Therefore the basic function prevent collision with obstacles” is intended to cover all hazards endangering moving trains and their passengers caused by intrusive elements outside trains
(e.g. cars, parts of infrastructure, tools for maintenance left on the track) into the clearance of guideway.
Therefore the basic function prevent collision with persons’ is intended to cover all hazards for persons who are endangered by moving trains caused by intrusion into the clearance of guideway (e.g. fall into platform track) or while present beside moving trains (e.g. waiting at platform edge).
6.5 Hazards associated with “supervising passenger transfer”
In grade of automation UTO. the responsibility of on board staff for supervising the passenger transfer between platforms En stations and the train in order to prevent as far as possible Injuries to persons shall be mitigated sufficiently because operations staff is absent from the train. Theretoro
• the basic function ‘control passenger doors Is Intended to cover all hazards endangering passengers caused by unintentional opening and closing 01 passenger doors,
• the basic function “Prevent person injuries between cars or between platform and train is intended to cover all hazards endangering passengers while passing between platform and train caused by gaps between cars of a train and between car body and platform edge,
• the basic function “Ensure safe starting conditions” is intended to cover all hazards endangering persons caused by unexpected starting of trains (e.g. train start with open doors, train start with trapped obstacle between door leaves).
6.6 Hazards associated with “operating a traln’
In grade of automation LJTO, the responsibility of on board staff t or operating a train in order to prevent as far as possible unsafe situations lot passengers shall be mitigated sufficiently because operations staff responsible for operating a train is absent.