Irish Railway Record Society
Journal 173 Accident Reports
RAIL ACCIDENT INVESTIGATION UNIT
The
RAIU is a functionally independent investigation unit of the Railway Safety
Commission and it has issued a report into the derailment of a ballast regulator
at Limerick Junction.
At approximately 04:50 on
3 July 2009, ballast regulator 703 and tamper 743 were travelling coupled
together from a work site on the Dublin side of the station when leading machine
703 derailed when entering the down sidings. Both On Track Machines (OTMs) were
owned by IÉ and were operated by Lloyd Rail. There were no injuries or damage
to the OTMs as a result of the derailment. The tip of the left switch rail of
27A points was bent and broken, the second stretcher bar was bent and four
chairs were damaged.
Trailing crossover 27 allowed access between the down sidings and the down main line. Points 27A were 90-lb bullhead-rail points that were originally installed in 1947 and were operated mechanically by wire from Limerick Junction South Signal Cabin.
The leading left wheel of 703 did not follow the diverging route set into the sidings, but travelled over the top of the left switch rail of the points and along the stock rail. The right wheel of the leading wheelset of 703 and the second wheelset followed the correct route. The two wheels on the leading wheelset of 703 derailed as the route of the wheels diverged.
The last inspection of 27A points in accordance with IÉ standards was carried out on 25 April. The records for this inspection show they were rated at 30%. The tip of the left switch rail was recorded as being in poor condition and the switch was recorded as not being square. Track gauge was outside range, condition of timbers was “poor”, chair/baseplate gall or timber indentation was “poor”, stock rail bolt tightness was “poor” and sleepers needed packing. The points were considered by IÉ to be life expired and were due to be removed by October 2007 as part of the Limerick Junction re-signalling scheme. However, this project has been delayed.
The 24-week and annual inspections of the ballast regulator include checking wheel profile. “The wheel profile inspections were found not to have been carried out. The maintenance instructions did not clearly state that measurement of the profiles was required. The IÉ staff responsible for the maintenance of the OTMs were not trained to measure the wheel profiles.” The records of the last inspection, which was completed on 25 June 2009, indicated that only a visual inspection of the wheel profiles was carried out as part of the maintenance. Full annual inspections were completed on 25 February 2009, 17 November 2008 and 22 February 2008. “Checklists for these inspections have no entry against the checking of the wheel profiles indicating that they were not carried out”. Wheels on 703 were last re-profiled on 13 and 14 January 2003.
“No defined wheel profile was available for the Regulator. General minimum acceptable limits for flange dimensions have been set by IÉ for any wheel profile used on the network, beyond these limits the wheel must either be re-profiled or scrapped.” Wheel profiles for 703 were checked following the derailment and the leading wheelset “was found not to meet the minimum acceptable limits for wheel profiles on the IÉ network...”
“The profiles of the wheels on unit 703 were not checked following two derailments prior to the derailment on the 3rd of July 2009. Had the profiles been checked, unit 703 would have been removed from operation until the wheel with a profile below the acceptable limits for wheels on the IÉ network was re-profiled.”
“The movements of the train through Limerick Junction Station could be observed on the station Closed Circuit Television footage. It was possible to confirm that the train was not travelling at excessive speed leading up to and at the time of the derailment.”
The report found the immediate cause of the accident was:
 |
“The derailment of the wheels as a result of the wheels taking diverging routes on the track due to the poor interface created by degraded condition of the switch rail and the wheel profile.” |
The causal factors
identified were:
|
“The poor condition of the number 27A points; |
|
The flange sharpness of the wheels on the leading wheelset of the On Track Machine.” |
The underlying factors were:
|
“The lack of measurement of the wheel profiles as part of the maintenance of the On Track Machine; |
|
The lack of measurement of the wheel profiles following previous derailments of the On Track Machine.” |
The RAIU issued two recommendations:
|
Iarnród Éireann should put in place a formalised process to ensure that life expired points are removed from service, where this is not possible a risk assessment should be carried out and appropriate controls should be implemented to manage the risks identified; |
|
Iarnród Éireann should ensure On Track Machine maintenance personnel are trained and competent to examine the wheelsets |
The report noted as of 8 of June 2010, IÉ had advised that the following actions had been taken in relation to the accident:
|
Points 27A and 27B were renewed following approval in October 2009; |
|
OTM maintenance staff have been trained in wheel measurement; |
|
Procedures have been altered so that OTMs have their wheels measured as part of their annual service; |
|
All annual service sheets for OTMs have been amended to include wheel measurements and records are retained for audit and inspection purposes. |
