Merseyrail Punctuality Figures

[SheffStudent]

Hi,
I am a student current studying in Sheffield and I am looking for some clarification on some figures.

My issue is with the figures that state Merseyrail is frequently among the top performing operators for punctuality in the country.

http://www.networkrail.co.uk/about/performance/
http://www.liverpoolecho.co.uk/news/...ompany-3347168

http://www.passengertransport.co.uk/...tuality-claim/

My two questions are;

Can someone explain the difference between RTP and PPM, mentioned in the third link.

RTP = Right Time Performance (percentage of trains arriving early or
within 59 seconds of schedule) over year to December 8, 2012.
PPM = Public Performance Measure over year to December 8, 2012.

And if there many be factors which push these figures up to such a high standard, such as train cancellations not being included.

I am originally from Merseyside and based on personal experience, recently viewed twitter pages such as #Merseyfail and #MiseryRail, I am very sceptical of these figures.

Any help would be brilliant but anything that is sourced, especially by Journals or credible newspapers would be more useful.

Thanks

[johnmoly]

Well, I can't answer your queries, but, I use the Merseyrail network nearly every day, since 2006, and 99% of the time they are punctual. Even when a train will be one minute late the platform electronic information panel will say so. The MiseryRail nickname stands for the overcrowding on the peak services where they do not have enough carriages to satisfy demand, something they are working on for the new stock, whenever that will be !
As they run nearly 800 trains per weekday, I think it's a good service.

[Beeyar Wunby]

RTP is exactly what it says - the percentage of trains within the time slot.

PPM contains an element of weighting, so that different TOCs with very different routes/traction/services can be compared with each other. It also takes into account Failures and Cancellations.

The significance of the PPM is that is used as an indication of how well a TOC is performing in terms of its franchise commitment.

HTH