forward to "pin down" the handles of the brakes, so the brakes were partially applied during the descent. Early goods vehicles had brake handles on one side only but, from about 1930, brake handles were required on both sides of good vehicles. Trains containing hand-braked vehicles were described as "unfitted": they were in use in Britain until about 1985. From about 1930, semi-fitted trains were introduced, in which goods vehicles fitted with continuous brakes were marshalled next to the locomotive, giving sufficient braking power to run at higher speeds than unfitted trains. A trial in January 1952 saw a 52-wagon, 850 ton, coal train run at an average of , compared to the usual maximum speed on the Midland main line of for unfitted freight trains. In 1952, 14% of open wagons, 55% of covered wagons and 80% of cattle trucks had vacuum brakes. In the early days of diesel locomotives, a purpose-built brake tender was attached to the locomotive to increase braking effort when hauling unfitted trains. The brake tender was low, so that the driver could still see the line and signals ahead if the brake tender was propelled (pushed) ahead of the locomotive, which was often the case. By 1878 there were over 105 patents in various countries for braking systems, most of which were not widely adopted. Continuous brakes As train loads, gradients and speeds increased, braking became a more significant problem. In the late 19th century, significantly better continuous brakes started to appear. The earliest type of continuous brake was the chain brake which used a chain, running the length of the train, to operate brakes on all vehicles simultaneously. The chain brake was soon superseded by air-operated or vacuum operated brakes. These brakes used hoses connecting all the wagons of a train, so the operator could apply or release the brakes with a single valve in the locomotive. These continuous brakes can be simple or automatic, the essential difference being what happens should the train break in two. With simple brakes, pressure is needed to apply the brakes, and all braking power is lost if the continuous hose is broken for any reason. Simple non-automatic brakes are thus useless when things really go wrong, as is shown with the Armagh rail disaster. Automatic brakes on the other hand use the air or vacuum pressure to hold the brakes off against a reservoir carried on