could be applied. The machines also have blinking red lights to warn following trains that a train is ahead. With the introduction of the ETD, the conductor moved up to the front of the train with the engineer. A 1982 Presidential Emergency Board convened under the Railway Labor Act directed United States railroads to begin eliminating caboose cars where possible to do so. A legal exception was the state of Virginia, which had a 1911 law mandating cabooses on the ends of trains, until the law's final repeal in 1988. With this exception aside, year by year, cabooses started to fade away. Very few cabooses remain in operation today, though they are still used for some local trains where it is convenient to have a brakeman at the end of the train to operate switches, on long reverse movements, and are also used on trains carrying hazardous materials. CSX Transportation is one of the few Class 1 railroads that still maintains a fleet of modified cabooses for regular use. Employed as "shoving platforms" at the rear of local freight trains which must perform long reverse moves or heavy switching, these are generally rebuilt bay-window cabooses with their cabin doors welded shut (leaving their crews to work from the rear platform). BNSF also maintains a fleet of former wide-vision cabooses for a similar purpose, and in 2013 began repainting some of them in heritage paint schemes of BNSF's predecessor railroads. Types The form of cabooses varied over the years, with changes made both to reflect differences in service and improvements in design. The most commonly seen types are: Cupola or "standard" The most common caboose form in American railroad practice has a small windowed projection on the roof, called the cupola. The crew sat in elevated seats to inspect the train from this perch. The invention of the cupola caboose is generally attributed to T. B. Watson, a freight conductor on the Chicago and North Western Railway. In 1898, he wrote: The position of the cupola varied. In most eastern railroad cabooses, the cupola was in the center of the car, but most western railroads preferred to put it toward the end of the car. Some conductors preferred to have the cupola toward the front, others liked it toward the rear of the train, and some just did not care. ATSF conductors could refuse to be assigned to a train if