50339 Reflections make digital speedometers difficult to read

May 2012 in Network Rail and Suppliers

Equipment Rolling stock Work environment Wales

An ERTMS unit includes a screen which displays a digital readout of the speedometer. However, this readout displays in white on a black background, leaving it virtually impossible to read when a Driver's shirt causes a white reflection on the screen. With Drivers unable to monitor train speeds during this time, the reporter believes there is an increased Signal Passed at Danger (SPAD) risk.

Drivers were able to read the original speedometers without any difficulties before the ERTMS units were installed. Once installed, these speedometers were disabled and it is not known whether the old speedometers and the ERTMS units can be used simultaneously. If this is possible, it would provide Drivers with an alternative way of monitoring their speeds.

The reporter is aware that the screens of the ERTMS units were changed from a gloss finish to a matt finish when reflection issues were initially discovered, but this has not eliminated the problem. Once it was found that wearing black prevented reflections, Drivers at Machynlleth depot were issued bla

The reporter states that Network Rail is sponsoring the implementation of ERTMS whilst the in-cab equipment is manufactured by Ansaldo STS.

Could Network Rail:

• Use its influence to consult Ansaldo STS regarding whether changes could be made to the digital writing and background colours on the speedometer screen to make    it more legible in sunny or bright conditions?

 Could Arriva Trains Wales:

• Consider activating the old speedometer to work simultaneously with the ERTMS units if this is possible?
• Consider issuing all Class 158 Drivers with black shirts?
• Provide shading on the dashboard to reduce reflections on screens?

Response from Network Rail

Network Rail would like to thank the reporter for bringing their concerns to our attention.

Could Network Rail use its influence to consult Ansaldo STS regarding whether changes could be made to the digital writing and background colours on the speedometer screen to make it more legible in sunny or bright conditions?

Network Rail has worked hard with Ansaldo STS and Arriva Trains Wales (ATW) to improve the speedometer screen in the Class 158s, both in bright daylight and at night. We have also worked closely with the ATW Driver Council to incorporate their suggestions and comments. We are pleased to confirm that further improvements have been agreed with the Drivers Council and will be implemented in the next few months.  

We recognise that the Class 158 in particular presents a set of complex problems for Driver Machine Interface (DMI) legibility caused by reflections and washout in bright sunlight due to the constraints imposed by the cab layout and size. The DMI initially fitted to the Class 158 has proven to be unsatisfactory for the Drivers when in service. All DMIs have now been replaced with a new DMI which uses the latest approved flat screen technology. This screen is brighter to combat reflectivity and washout during sunny conditions and is able to be dimmed to very low levels of light at night to suit the Drivers needs. Since implementing this upgrade further consultation with the Drivers Council has identified additional improvements.  Our target date for rolling out additional improvements is 29 November 2011. ​

 Response from Arriva Trains Wales

ATW would like to thank the reporter for making their views known.

In response, we can confirm that significant work has gone into resolving the issues of reflectivity and screen 'washout' associated with the initial installation of the Driver Machine Interface (DMI) screen on European Rail Traffic Management System (ERTMS) fitted Class 158 trains.

The first DMI used proved to be incapable of preventing reflectivity or screen washout and so a second improved DMI was installed. This was subject to testing and union consultation prior to use.

Although the situation improved, the second DMI had some shortcomings so a decision was taken to install further cab equipment to address concerns. Extra side window blinds, window tinting and a moveable DMI tinted cover were all introduced. These controls and their effectiveness when used with the second DMI were subject to an independent review which considered both Driver operability and DMI performance in terms of human factors.

The reports concluded the DMI and the additional control measure were sufficient but also recommended that darker shirts would be required for full ERTMS operation (in order to read all of the DMI system functions and messages). The reports also noted that the view of the speedometer on the DMI was acceptable without additional controls.

Currently, ATW, Network Rail and Ansaldo are also actively engaged in the testing of a third version of the DMI with the goal of being able to remove the extra cab equipment, though the tint on the side windows will remain.  

In addition to those control measures noted above, the Class 158 cabs have gone through a refurbishment program which included a repaint of the cab interior. This has been done in a dark matt grey colour to further reduce the effect of any reflections and/or washout.

ATW Drivers have been issued with instructions regarding the use of the DMI which tell them to employ theRule Bookinstructions related to the control of a train with a defective speedometer if they experience excessive screen washout in bright conditions. 

The colours and fonts used on the DMI are subject to European technical standard requirements and cannot be changed at this time. The colours and layout of the DMI are in use across the EU.

ATW and Network Rail have been using Driver feedback during the monitoring phase of ERTMS implementation. ATW have been running ERTMS user workshops with the minutes of these fed back to the ERTMS project team.

Finally, ATW have considered the possibility of activating both the DMI and secondary analogue speedometer at the same time. This option has been rejected as the DMI takes a digital reading of train speed which means that the speedometers would be likely to display slightly different speeds and present an unnecessary distraction to the Driver.