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Fleet Availability Progress - 14/01/2020

Following our last progress report just before Christmas there are several updates to share with you:

  • All power door silver set trains and Class 172 trains are now back in service following recent repairs.
  • Unfortunately, as mentioned in our previous update, one of our 4 car trains suffered an operational incident.
    This train will be sent away for structural repairs during the week commencing 12th January.
    It is likely that the train will be out of service for 5-6 months.
  • Following a challenging end to the leaf fall season, we have two vehicles awaiting wheelset changes.
    The required material is on site at Aylesbury depot and work is scheduled to be completed this week. 
  • Currently the wheel lathe at Aylesbury depot is defective and unable to reprofile defective wheelsets.
    Work to repair this piece of equipment is a high priority and the we expect the work to be completed over the next few days.

All other vehicles currently at the depot are stopped for scheduled maintenance activities.

Seats Provided as at 14 January 2020

Since the previous update there have been a number of issues which have impacted the reliability of our service these include: 

  • An operational incident which resulted in some significant damage to one of our 4 car trains. This train will need to be sent away for structural repairs early in the new year and it is likely that it will be out of service for 5-6 months.  
  • Over the leaf fall period, our slam door silver train suffered from wheel flats. As this train is unique in our fleet, we have limited opportunity to supplement with additional vehicles and as such this train is currently operating with one vehicle short.  
  • Currently there are two trains out of service awaiting tyre turning. This is due to be completed before Christmas.  

However, one of our trains which has been out of action for nearly a year due to some significant derailment repairs, has now been fully repaired and returned to passenger service. Additionally, following a 5-month programme to ensure our power door silver set trains meet all mandatory accessibility upgrades, these trains are now back in service along the route. 

All other vehicles currently at the depot are stopped for planned maintenance reasons. 



Fleet Availability Progress - 05/12/2019

Following our previous fleet availability update, there have been a number of issues which have caused some problems regarding the reliability of our service. These include:

•    Two of our trains which are awaiting an alternator raft change. One was delivered this past weekend, with another due to be delivered into Aylesbury by the end of this week. 
•    A train that was damaged last week following an operational incident at our Wembley depot. The train will be inspected shortly and a return to service date will be determined following this. 
•    Two carriages that have been taken out of service for repair due to wheel damage sustained during leaf fall. 

However, on Monday 9th December, the last of our Silver Set trains which have been undergoing accessibility upgrades will be back in service which will aid us in outputting the correct amount of trains.

We’re committed to improving our fleet availability by following the actions listed in our last update. With the release of the additional trains, we are confident we can offer a more consistent train service delivery over the coming weeks. 

The graph below shows how we are doing at providing the correct number of seats to make our trains their planned length in the morning peak.

Fleet Availability Progress - 051219



Fleet Availability Progress - 11/11/2019

Since the previous update the Engineering team have continued to work hard to address the fleet availability challenge. We have recently seen a significant improvement in trains being available for service and fleet performance is recovering back to the previous high levels of reliability. The recovery actions shared previously are now being completed and fleet availability is returning to the required levels. A few of these actions are:

  • Scheduled maintenance programmes are now back on plan
  • The delivery of key materials has improved and work continues to reduce the risk of further material shortages
  • Increased management focus on fleet reliability issues and defect repair
  • Introduced additional staff resource to expedite train toilet repairs

Short Form Update Graph

We now regularly output the correct number of train types, but we are still reliant on the completion of a number of activities before we can confidently output the correct amount of all trains. These are:

  • The completion of the long term stopped train following a derailment – Expected return to service date 25th November
  • The completion of the silver set accessibility compliance modifications – Expected completion by 13th December

The completion of these two activities will effectively allow the release of two additional trains, which will allow a more consistent train service delivery.

Thank you for your understanding, we will continue to keep you updated on progress.



Fleet Availability Update - 11/10/2019

Dear Customers,

The availability of our fleet continues to be an area of focus for Chiltern Railways. We have seen improvements in the situation over the past two months, but there still remains work to do to offer you the reliable and comfortable service you deserve. 
Since the previous update the Engineering team have continued to work hard to address the ongoing fleet short form issues. A number of activities have been completed which have started to demonstrate an improved fleet availability position and this will continue to increase the number of trains we can reliably provide for service. We have: 

  • Reviewed the required scheduled maintenance to allow a greater throughput of trains at the depots 
  • Had an increased numbers of Engineering staff available to rectify defects and undertake scheduled maintenance 
  • Worked closely with our suppliers to improve the delivery of key materials and to de-risk further material shortages 
  • Worked closely with train owners to develop toilet repair processes and improve material supplies 
  • Introduced alternative tyre turning facilities at external sites 

We now more regularly output the correct number of certain train types, but we are still reliant on the completion of several activities before we can confidently output the correct amount of all trains. These are: 

  •  The completion of repairs to a long term stopped train following a derailment – Expected completion date 13th November 
  • The completion of the modifications to our Silver Set trains in order that they comply with accessibility regulations – Expected completion by December 

The completion of these two activities will effectively allow the release of two additional trains, which will allow a more consistent train service delivery. 

Please accept our apologies for the lack of capacity over recent months, we will continue to keep you updated on the situation as we work to resolve it.


Alan Riley

Customer Services Director, Chiltern Railways



Fleet Availability Progress - 22/08/2019


Dear Customers,

Please accept my apologies for the ongoing disruption caused by trains needing maintenance. I know how frustrating it is when your train turns up and it’s shorter than normal. We recognise that this has caused uncomfortable journeys for customers who have been unable to get seats or not board their service at all. Clearly, this isn’t the service you have come to expect from Chiltern with our industry leading performance and passenger satisfaction scores. Here I have tried to explain why your trains have recently been shorter than normal.

What has gone wrong?

Recently we have been unable to provide the required number of carriages each day to run trains of the lengths intended in our timetable. When this happens, we are forced to make decisions on which services will be shorter than planned in order to minimise disruption for the whole route. This has led to overcrowding on certain services and uncertainty for our customers as to what kind of journey they can expect.

A train that is shorter than usual is called a “short form”. Our commuter trains are made up of one or two shorter trains coupled together to make one long train. If we are unable to couple together the usual amount of trains, we end up with a shorter train than usual. Unfortunately, this means there are fewer seats than usual, which makes peak time trains overcrowded – we are very sorry for the inconvenience this causes.

What causes a short form?

A short form is usually because a train or carriage is out of action. This might be due to a fault or due to damage, or it might be because the train is undergoing one of its routine service checks. There are very strict safety guidelines for train maintenance, which is one of the reasons why the UK’s railways are the safest in Europe.

Why has this happened?

There is no one cause of this situation, but rather several different factors which have come together in the last few months. Chiltern Railways has a variety of train types which have been acquired over the length of our 20-year franchise. Over the years we have provided new services and increased the lengths of trains in response to customer demand. This has put a strain on our fleet as only a very small number of carriages are able to be stopped at any one time for maintenance without impacting the service you receive.

Many of our trains are nearly 30 years old and we have had problems getting parts as suppliers reduce their support in manufacturing new components, particularly around ageing electronic control systems. Another factor is the large number of Wembley events which have reduced the time available for maintenance and repairs to take place and an unforeseen level of wheelset damage which requires the trains to be removed from service until the wheels can be changed or repaired.

Additionally, new legislation is due to come into effect at the end of the year regarding accessibility requirements for trains. This means that our Silver Sets are being sent away, one at a time, for modifications to comply with these standards and this has placed further demand on the fleet.  In addition, we have had a number of trains stopped for long term repairs after specific incidents including one train which was derailed and damaged at our depot.

What are we doing about it?

Our engineering and performance teams are working hard to stabilise the position and get back to the point where we can offer the full number of carriages to our customers. We now have a three-month action plan to define the steps we are going to take to address the situation and will be sharing these with the Chiltern Passenger Board. These include:

  • Starting a programme to overhaul the electrical power systems on our Class 165 trains which have proven unreliable in recent times, particularly during the hot weather.
  • Changing our approach to heavy maintenance to optimise the amount of time this takes on each train.
  • Reviewing our processes for how we maintain our trains' wheels in an effort to reduce the current high levels of damage seen.
  • A review of the required staffing levels at our depots and ensuring optimised working processes.
  • Working with our supply chain to build up stock levels of critical components
  • Continuing to seek out all suitable additional rolling stock.

How can I find out if my train is shorter than usual before I arrive at the station?

We publish information about which trains are shorter than normal on JourneyCheck. You can sign up for automatic alerts to your inbox via

What are our longer-term plans?

Whilst we would like to be in the position of leasing new trains this is unlikely to happen before the end of the current franchise in 2021. There is a national shortage of diesel rolling stock which would be appropriate to run on the Chiltern lines. Even when some does become available, there is a preference from the Rolling Stock Companies who own these trains to lease them to new franchises with longer contracts in place. Instead we are looking at a range of options including standardising the lengths of some types of trains to free up extra seats during the morning and evening peaks, and exploring the expansion of one of our depots to increase our maintenance capacity.

Please be reassured that we are working hard to get the fleet back to the position where we can consistently provide the number of seats required. Thank you for your patience and for bearing with us whilst we implement this plan.

Alan Riley

Customer Services Director, Chiltern Railways