Jacobs bogie

Jacobs bogies (named after Wilhelm Jakobs,, 1858–1942, a German mechanical railway engineer) are a type of rail vehicle bogie commonly found on articulated railcars and tramway vehicles. Instead of being underneath a piece of rolling stock, Jacobs bogies are placed between two carriages. The weight of each carriage is spread across the Jacobs bogie. IC3 by Adtranz, the JR Central L0 Series maglev and the Škoda ForCity tram. In Australia, Jacobs bogies were first used in 1984–85 on B class Melbourne trams, which were designed to run on two former suburban railways which had been converted to light rail operation.

A number of intermodal freight trains, such as the Pacer Stacktrain run by US logistics company XPO Logistics, use container well cars joined in groups of three to five, with four side bearings on top of the bolster of a standard North American bogie between the individual cars.

Some triple bogied two section electric locomotives such as the NZR EW class have an articulated body supported on the centre bogie. Other types of Bo Bo Bo locomotives instead use a body shell that has enough allowance for sideplay in the central bogie.

The Jacobs bogie can be found in trams (streetcars) such as the Tatra K2 and Oslo's SL79. The first 100% low floor tram with pivoting bogies, the Škoda ForCity, also uses modified Jacobs bogies.

On this crossover between the tram (streetcar) and the high speed train, Jacobs bogies occurred on the latest equipment of any significance, the two Electroliner trains (1941–1976). They were suited for streets with tight curves, the Chicago El and running through the countryside at approximately They served the Chicago–Milwaukee line and later the Philadelphia area.

Safety, because the trains are less prone to collapse like an accordion after derailing. A Eurostar train has been recorded as having derailed at a speed close to 300 km/h with no resultant loss of life or severe injuries among its passengers. Lower weight and simpler and cheaper construction because bogies are heavy, expensive, and complex structures. Less rail squeal and other wheel to rail noise because of fewer bogies.

The cars of the vehicle/unit are semi permanently coupled and can only be separated in the workshop. However, some flexibility may be achieved by coupling two or three units together into one train. Fewer bogies and fewer wheelsets mean greater axle loads – if everything else is equal.