■ Outcomes - The two in-service derailments in the first year of the PPPs is consistent with the trend reported by LUL since 1993-94, with derailments ranging from 0 to 4 each year around an average of approximately two per year.9
■ Processes - None of the derailments in the first year of the PPPs have led to any changes in the contract or safety cases but, as a result of the investigations into these derailments, there may be changes to some LUL safety and engineering standards. For example, the formal investigation following the Hammersmith derailment recommended improvements to track inspection, including possibly undertaking track inspections during daylight; better lighting for night-time inspections; review of risk assessments for patrolling; improved guidance on the equipment used by patrollers; and an improved system of ultrasonic testing.
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9 Figures complied by the Health and Safety Executive show a similar trend in the last 10 years, with some discrepancies between the two data sets due to factors such as different recording and clarification systems.