Network Rail herbicide agreement shields drinking water from pollution

An agreement between water companies and Network Rail for the herbicide used to keep tracks clear not to pollute waterways is now protecting more than 600 vulnerable sources of drinking water from pollution.

Eight "spray trains" (one pictured) cover hundreds of miles every night to prevent over-growing plants and weeds – and ice when temperatures drop – from disrupting train services.

Thames Water first launched a project in London and the Thames Valley in the 1990s to work with Network Rail’s predecessors to ensure the chemicals used did not pollute waterways, which often run parallel to rail lines. Now there are agreements in place to benefit all water companies and customers across England and Wales.

Dr Dinah Hillier, a Thames Water scientific services manager, said: “We’ve worked closely with Network Rail to influence the types of herbicides they use and how they’re applied so they are less likely to contaminate water, and we’re delighted with the results.”

The agreement now protects more than 600 vulnerable drinking water sources from herbicides that, if they reached the water, would require removal using expensive and energy-intensive advanced treatment processes.