'Passengers in Excess of Capacity' (or 'PiXC') is an overcrowding indicator established and monitored by the Department for Transport (DfT).  Under the franchise agreements between the DfT and the train operator, the operator has an obligation to produce a Train Plan to demonstrate that it is planning its timetable and allocating rolling stock in a way that best reconciles its available capacity with passenger demand to keep overcrowding to a minimum.

The standards set by DfT for PiXC are for loadings of no more than 4.5% above capacity for any one peak and no more than 3% above capacity across both peaks. No penalties are levied on operators which fail to meet these standards, however.

How is PiXC measured?

The PiXC measure is applied to trains arriving in London between 7.00 am and 9.59 am and then again for trains departing from London between 4.00 pm and 6.59 pm.

For journeys of more than 20 minutes, which should cover all commutes using mainline services from Sevenoaks to London, capacity is defined as the number of standard class seats.  For journeys of 20 minutes or shorter, an allowance for 'normal' standing room of around 35% of the number of seats (the exact figure depends on the type of train) is also added.

Source: Office of Rail Regulation / Strategic Rail Authority, 'National Rail Trends'.

Overcrowding at an acceptable level?

The chart above compares actual conditions for Outer Kent (Mainline) services with the standards. (Annual observations below the dashed lines indicate that the standard has been met.)

There was apparently a marked reduction in measured overcrowding after 2002 (the am peak figure for that year appears to be an outlier), with both standards being met in 2003-04.  However, the position deteriorated in 2005 with both targets being missed.  This may partly be associated with the introduction of new trains which have fewer seats than the old ones.

Moreover, we are sceptical of the way the data are compiled.  For example, if a mainline train stops at Chelsfield, it is deemed to fall into the '20 minutes or less', 'Inner Kent' category, so its assumed capacity is increased by around a third because of the addition of the  'acceptable' level of standing room factor.  In our view this treatment biases the results.

Note also that the PiXC standard does not apply to trains leaving London from 7.00 pm onward.  Moreover, the data are only estimated once per year on a 'typical weekday' in the autumn.  We doubt that this is a sufficiently reliable way of gauging the problem, particularly at a time when the pattern of commuting is changing.

The situation for Inner Kent ('Metro') services is better than for long distance. This is particularly the case with the evening peak. When the Outer and Inner Kent data are combined, the average for the Kent franchise as a whole compares favourably with most other London and South East operators. Unfortunately, this is not of great comfort to Sevenoaks area travellers, particularly those using mainline evening peak services which stop at Chelsfield.

What can be done for Sevenoaks area commuters?

First, the operator should admit to the seriousness of the problem and the impact it has on passenger sentiment by measuring overcrowding more frequently and more accurately. We understand that some new trains are have equipment that monitors passenger loading.

Second, there is the nitty-gritty approach of using available capacity more efficiently.  The SRTA, after a close examination of the timetable and the allocation of existing rolling stock, has regularly made proposals to the operator to make adjustments to the timetable to release more seats for chronically overcrowded trains.  But one constraint is the inadequate power supply which on some parts of the network (for example south of Tunbridge Wells) restricts the maximum length of trains that can be run with some of the new rolling stock.

Third - and more fundamentally - we need more and longer trains, and lengthened platforms where track capacity can accommodate them. If platform lengthening has to be a long-term goal, then more trains should be equipped now with Selective Door Opening so that longer trains can safely make stops at stations with shorter platforms. Such improvements would also mean that those commuters who are forced to use Sevenoaks because of the limitations of the Maidstone East line would get a better deal nearer home.

Some pressure may be alleviated by the opening of the Channel Tunnel Rail Link, diverting some commuters using Ashford from trains stopping at Sevenoaks.  However we don't think this is enough.  The SRTA's recent 'Brief to GoVia' sets out some detailed proposals we have made to alleviate the problem.

Under-investment in rolling stock at a time of a strong prospective growth in passenger numbers given well-trailed planned housing development in Kent is unacceptable.  Planning has to be better joined up than has been the case.