Crawler Crane
The crawler crane is a particular kind of mobile crane that is available with either a lattice boom or a telescopic boom which moves upon crawler tracks. Since this model is a self-propelled crane, it is capable of moving around a jobsite and completing jobs without a lot of set-up. Because of their enormous weight and size, crawler cranes are fairly expensive and even difficult to transport from one site to another. The crawler's tracks provide stability to the equipment and enable the crane to function without the use of outriggers, although, there are some units that do use outriggers. Furthermore, the tracks provide the movement of the equipment.
Early Mobile Cranes
The first mobile cranes were initially mounted to train cars. They moved along short rail lines that were specially made for the project. Once the 20th century arrived, the crawler tractor evolved and this brought the introduction of crawler tracks to the agricultural industry and the construction business. Not long after, excavators adopted the crawler tracks and this further featured the versatility of the machine. It was not long after when crane manufacturers decided that the crawler track market was a safe bet.
The Very First Crawler Crane
Northwest Engineering, a crane company in the USA, was the very first to mount its crane on crawler tracks in the 1920s. It described the new equipment as a "locomotive crane, independent of tracks and moveable under its own power." By the mid-1920s, crawler tracks had become the preferred means of traction for heavy crane operations.
The Speedcrane
Developed by Ray and Charles Moore of Chicago, Illinois; the Moore Speedcrane was one of the first to attempt to copy rail lines for cranes. Made within Fort Wayne, Indiana, the Speedcrane was 15 ton, steam-powered, wheel-mounted crane. In 1925, a company called Manitowoc Shipbuilding Co, from Manitowoc, Wisconsin recognized the marketability and the potential of the tracked crane. They decided to team up with the Moore brothers to be able to produce it and go into business.