Train lights

This replica of Union Pacific No. 119 includes a typical 19th century locomotive headlight

The earliest trains did not run at night, but the need for running trains at night soon became apparent. In the United States, early records of headlight usage date back to 1832: that year, Horatio Allen devised the first known locomotive headlight - though his "headlight" consisted of a burning pile of wood on a flatcar, followed by a giant reflector on a second flatcar, pushed by a locomotive.[3] While this method of illumination was impractical, other experimentation continued. One early method was to hang a number of lanterns off the front of a locomotive.[3] In the later 1830s, the first proper train headlight was built by two mechanics in New York: a box made of sheet metal and incorporating a reflector.[3] Mass production of locomotive headlights was started in 1838 in that state, and by 1850 they were a common sight on trains in the United States. By the dawn of the American Civil War, nearly every locomotive in the country was equipped with a headlight.[3]

Nickel Plate Road 2-8-4 No. 765 came with a twin-sealed beam headlight for most of its life.

Despite experiments and advances in headlight technology in the 1800s, the very idea of using headlights on trains was for a long time controversial. As late as 1886, a railroad official in the United States was quoted as saying "On a road engine the headlight is of no earthly use to the engineer; it obstructs his vision so that he cannot see his switch lights, and I think that every thinking engineer will come to the conclusion that he would rather run in the night without a lamp, than with it, as he can see better in the dark".[4]

Early headlights were fueled by oil, though kerosene-fueled headlights were developed as well in the 1850s. The discovery of electricity soon led to experiments with using it to power locomotive lights, with the first-known example, a battery operated light, being tested in Russia in 1874. In 1883, a railroad company in France also experimented with electrical lights, but the first example to go into production was designed by an American inventor in 1897. In 1915, the United States Congress passed a law mandating every train be equipped with an electric headlight, ending all debate about their utility.[3] Twin-sealed beam headlights were also invented after the end of World War II, and they were designed in a way where two lightbulbs are installed in one headlamp.[5]

Despite the widespread use of locomotive headlights in North America, in the United Kingdom trains typically ran without true headlights at night.[4] From the earliest days of British railways, it was decided that headlamps bright enough to usefully illuminate the path ahead of a train were both unnecessary and undesirable. Railways were legally required to be fully fenced off from surrounding land and road crossing were protected by gates. Unlike the many miles of lines running through sparsely-inhabited country in North America, British railways had manned signal boxes and stations at relatively short intervals, more comprehensive railway signalling (as opposed to American practice which quickly came to rely on Train order operation), and most public road crossings were staffed by dedicated keepers. Thus the risk of obstructions, wildlife, trespassers or loose animals on the line was significantly reduced and there was a good chance of it being possible to signal a train to stop before any accident occurred if the line was blocked. It was not necessary to fit trains with headlamps powerful enough to allow the crew to see usefully ahead, and it was reasoned that any such lamp would be so bright as to reduce the crews' night vision and reduce their ability to see the relatively dim oil lamps used in signals and carried by trackside staff. British trains did carry lamps on the front of the locomotive, but these were small, low-powered oil lamps only slightly larger than a standard hand-held lamp. They served only to indicate the approach and location of a train to others and were of no use to the crew on the locomotive itself. These headlamps were carried in different numbers, patterns and colours to indicate either the type of train (express passenger, stopping passenger, perishable freight, express freight and so on) or the route the train was taking. This allowed signallers to properly assign priority to trains. By the 1920s these headcodes had been largely standardised between the different railway companies, with the arrangements using between one and three white lamps mounted in four standard positions (one at the top of the smokebox door and three along the buffer beam. The lamps themselves were painted white to serve the same purpose by day, although some companies replaced the lamps with solid white discs for greater clarity. Diesel and electric locomotives introduced by British Railways initially retained the discs and four low-powered white lamps. This system of headcodes was abolished in 1960, with trains instead displaying a four-digit train reporting number on a large roller-blind screen mounted on the nose which was back-lit at night. This still provided no effective forward illumination. The reporting numbers were themselves withdrawn from 1976, with rolling stock being modified to show two low-powered white marker lamps which also served to indicate the presence of the train rather than throw light forward. Some locomotives and diesel multiple units working on remote lines in Scotland were fitted with single car-type headlamps alongside the two marker lamps to improve visibility at level crossings and to provide better visibility of wildlife and potential rockfalls on the track as local signal boxes and stations were closed. From the early 1980s - starting with the British Rail Class 58 locomotive and the Sprinter and Pacer multiple units - a single high-intensity headlight was fitted to new stock which, for the first time in standard British railway practice, served to illuminate the rails ahead of a train at night. Older stock was quickly retrofitted with similar headlamps, although the twin low-power marker lamps remained a requirement.

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