There is a large range of high-visibility clothing available. However, there is a particular specification for clothing that is allowed to be worn on the UK rail network. The specification is set out in Railway Group Standard GO/RT 3279:2012, a document that defines the ‘minimum requirements for high-visibility clothing for being conspicuous on the lineside or on or near the line’.
The GO/RT 3279 standard is based on the European standard EN 471:2003 + A1:2007. It requires garments to meet at least class 2 (the mid-point of a 3-class scale) of EN 471 for the minimum area of high-visibility materials used within a garment. Whereas the European standard permits several different colours of high-visibility materials, the railway standard specifies an orange colour.