Progress on metrication of the British rail network

Ronnie Cohen passes on an update on this topic that he has recently received from the UK Department for Transport.

In October 2013, Network Rail announced that it will be phasing out miles, chains and yards on the UK rail network and replacing these imperial measurements with metric units. Metric Views published an article on the metrication of the rail network in August 2014. You can read this article at http://metricviews.org.uk/2014/08/metrication-of-the-rail-network/.

I recently asked the UK Department for Transport about progress of the metrication of the rail network. In August 2020, I asked them the following questions in a Freedom of Information request:

“What progress has been made since 2013 to introduce metric units on the British rail network and planned changes in the future? What rail systems are using imperial units and what rail systems are using metric units?”

I received some brief information about some positive progress that has been made in the last few years and the desire to migrate the UK rail network to the metric system. Their reply was just two paragraphs long. Here is their reply:

“Targeted deployments of the European Railway Traffic Management System (ERTMS) on the GB rail network have been considered on a case-by-case basis. Where ERTMS is deployed, there is an aspiration for a migration to metric units. ERTMS operates on metric units; however, GB rail has a special exemption which allows us to display imperial units or metric units on the cab speed display. Initial phases of deployments are likely to use this special exemption with the cab speed display in imperial units, but with migration to metric units which will then ensure consistency with all the other metric units within the European Train Control System (ETCS).

Metric is currently used on Cambrian ETCS. Thameslink and Crossrail have maintained imperial for their ETCS operation. It is currently the intention for East Coast south ETCS to be in metric and LNER’s Azuma trains have the capability to operate in either metric or imperial, they currently operate in MPH ahead of ERTMS deployment.”

One thing I can add to their reply is that modern British tram and railway systems such as the Docklands Light Railway (DLR) and the Croydon tram network are entirely metric and use kilometres.

This article applies only to the GB rail network. A curious consequence of the history of railway development in the British Isles is that the track gauge on the island of Ireland is 1600 mm not 1435 mm that applies to the principal railways of the whole of western Europe including GB. While the gauges are different and will remain so, it is probable that other technical standards are converging.

One thought on “Progress on metrication of the British rail network”

  1. Trams and railways operate under different conditions – in general, tram drivers operate much like car drivers – they watch the line ahead for any problems. Train drivers are more like airline pilots – they operate using their instruments. In January 2018, UKTram published a useful book “Tramway Principals and Guidance” to replace guidance previously published by the Office of Rail and Road, and before that by HM Railway Inspectorate (https://uktram.com/wp-content/uploads/2018/07/Tramway-Principles-Guidance-Final-2.pdf). Of particular interest is paragraph 8.60(e) on page 52 which states the the speedometer shall be in km/h.
    Furthermore, the The Traffic Signs Regulations and General Directions 2016 (TSRGD – https://www.legislation.gov.uk/uksi/2016/362/schedule/11/made) defines the shape of tramway speed limit in Schedule 11, Part 2, Row 84. The TSRGD also specifies that the value shown is in km/h.

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