Janney couplers, the link-and-pin survived on forest railways. While simple in principle, the system suffered from a lack of standardisation regarding size and height of the links, and the size and height of the pockets. The link-and-pin coupler consisted of a tube-like body that received an oblong link. During coupling, a rail worker had to stand between the cars as they came together and guide the link into the coupler pocket. Once the cars were joined, the employee inserted a pin into a hole a few inches from the end of the tube to hold the link in place. This procedure was exceptionally dangerous and many brakemen lost fingers or entire hands when they did not get them out of the way of the coupler pockets in time. Many more were killed as a result of being crushed between cars or dragged under cars that were coupled too quickly. Brakemen were issued with heavy clubs that could be used to hold the link in position, but many brakemen would not use the club, and risked injury. The link-and-pin coupler proved unsatisfactory because: It made a loose connection between the cars, with too much slack action. There was no standard design, and train crews often spent hours trying to match pins and links while coupling cars. Crew members had to go between moving cars during coupling, and were frequently injured and sometimes killed. The links and pins were often pilfered due to their value as scrap metal, resulting in substantial replacement costs. John H. White suggests that the railroads considered this to be more important than the safety issue at the time. When a car happened to be turned 180 degrees one would have to look for a link. Railroads progressively began to operate trains that were heavier than the link-and-pin system could cope with. In Britain link-and-pin couplers were common on narrow gauge industrial and military railways, and eventually evolved into a form that could be reliably coupled when the train was stationary. Some preserved railways still use stock featuring a variety of link-and-pin couplers. The nowadays well established Scharfenberg coupler can be seen as evolved from the link-and-pin, by having double link-and-pin couplers and the links fixed with one per direction and the pins automatic. Link, pin and buffer Albert coupler To avoid safety issues, Karl Albert, then director at the Krefeld Tramway, developed the Albert coupler during 1921.