Response: OIA2019.50
21 October 2019
To
Via email
Dear
Information request for information on Mean Distance Between Failure statistics
I refer to your official information request dated 10 September 2019, asking for information
on Mean Distance Between Failure (MDBF) statistics for the different mainline locomotive
classes.
The attached Excel document shows the monthly faults, kilometres and MDBF by each class
of mainline locomotive, both in individual numbers, and as
6-monthly rolling average. As
you will note there is considerable fluctuation in the figures from month to month, which
means any analysis should look at long term trends.
You should also note that different generations of DL locomotives have different MDBFs,
with the later versions incorporating improvements which have resulted in better
performance.
Mean Distance between Failures is only one measure that is looked at when assessing
service performance. A more critical measure is whether a failure affected a service or not,
measured as a Service Affected Failure (SAF). A SAF is a failure that affects a train service
by more than ten minutes. Our focus is on the prevention of SAFs, as they are what affect
our On Time Performance and the service we can offer our customers.
Other factors that should be considered alongside the MDBF measurement are what line a
locomotive was travelling on, what sort of freight it was carrying and whether it was a just in
time or slower freight service.
Under s28 (3) of the Act, you have the right to seek an investigation and review of this
response by way of complaint to the Ombudsman. Refer to
http://www.ombudsman.parliament.nz for more information.
We trust this answers your query.
You have the right to seek an investigation and review by the Ombudsman of this decision.
Information about how to make a complaint is available at www.ombudsman.parliament.nz
or by calling free-phone 0800 802 602.
Yours sincerely
Dave
KiwiRail
Official Correspondence Unit
