Martin Bloomfield, Network Rail’s Ops and Dangerous Goods Specialist, and chair of the cross-industry Dangerous Goods Working Group, sheds light on dangerous goods transportation.
On 29 June 2009, a train carrying liquified petroleum gas derailed and caught fire at Viareggio, in Italy. Thirty-two people were killed and 26 were injured. One wagon struck the station platform and overturned. Many struck houses along the lineside. Two exploded.
The investigation found the most probable cause of the derailment to have been a broken axle, though one wagon was penetrated by lineside equipment, which led to the fire. The wagons had not been adequately maintained. They should not have been carrying dangerous goods.
Dangerous goods (DG) are exactly what they say they say they are – goods that are a risk to health, safety and the environment when transported. On GB rail, we move DGs very often, and very safely. And it’s not just about the rolling stock – think about the work train preparers do in making sure trains hauling DGs are properly marshalled and consigned for safe delivery.
But did you know that each transport mode has its own set of international rules and instructions for movement by road, sea, waterways and air to allow consignments to travel across borders? Thanks to Viareggio, trains carrying DG must also comply with the International Carriage of Dangerous Goods by Rail (RID) 2023, which is supported by 46 contracting states.
Every DG consignment is given a unique United Nations Number, which stipulates how transportation may take place, based on hazard classification, packing group, labelling, placarding, type of packaging to be used (including tanks and intermediate bulk containers), plus any special provisions that may apply, including hazard identification for the emergency services.
Each company that transports DG must by law have its own certificated Dangerous Goods Safety Adviser, known as a DGSA. Their role is to support, monitor and provide advice to ensure that each business complies with the necessary RID requirements. A DG safety incident has the potential to cause an impact both from a safety and environmental aspect, as witnessed at Llangennech in 2020 and more recently in East Palestine, Ohio. On GB rail, DG is usually carried in specially designed tank wagons, or containers.
The Total Operations Processing System, introduced by British Rail in 1974, is the database which manages and governs freight movement in this country. As such, DG commodities are documented as part of the train list, with their consignment UN number and a two-letter alpha code used to aid emergency specialist support.
An interesting fact about DG is that it may be shipped in ‘limited quantities’, which authorises small amounts of a consignment (litres or kilogrammes) to be transported without the full DG certification required, to your door, for example.
Deodorant aerosols (classified as UN1950 AEROSOLS asphyxiant) fall into this category. These may be transported in limited quantities in the appropriate package, providing this does not exceed 1 litre with the above symbol clearly displayed.
Interestingly, DG transportation by road is similar to rail. In comparison, a typical road tanker holds approximately 44 tonnes, whereas train capacity per tank wagon is 75 tonnes (a typical formation of 25 wagons equates to 1,875 tonnes). Clearly a train consignment is a much more sustainable option.
The nine classes of dangerous goods are:
Corrosives
Explosives
Flammable gases
Flammable liquids
Flammable solids
Oxidizing
Radioactive
Toxic and infectious
Miscellaneous