A crawler crane is a track-based vehicle that has a crane apparatus attached to it. These cranes are able to work on soft ground due to the weight dispersal properties of the tracks. A crawler crane is made more stable by the steel tracks and can lift much more weight than a rubber tire-equipped model with the same crane attachment.
The basis for a crawler crane is the track propulsion system. The continual track system is based on a late 1800s design. The wide steel tracks allow the crane to operate on much softer ground than a rubber tire-equipped crane. The tracks also allow much greater stability due to the increased ground contact. A benefit of a crawler crane is that it is maneuverable and versatile while on a job site.
There are problems with the crawler crane, one of the greatest being its enormous size. Some crawler cranes are so large that they must be taken apart and moved from one job site to the next by truck or by train. The massive size and weight allows the largest crawler cranes to lift loads as great as 3,500 tons to massive heights and then maneuver them into position. This massive size, however, comes with a cost. The cost is the difficulty in transporting the crane.
The crawler crane is composed of various parts. The tracks and propulsion system form the basis of the machine. On top of the tracks sits the engine, control area and the cab. Rising high above the cab is the boom. The cables run up through the boom and attach to the object to be lifted. Often a crane will have a small extension on the end of the boom that sticks out almost horizontally from the boom. This is called the jib and allows the crane to move objects further away from its center.
One of the features that allow a crawler crane to lift such enormous loads is a counterweight. Some of the larger crawler crane counterweight assemblies weigh as much as several hundred tons. Many crawler cranes have booms that reach several hundred feet in the air. Such reach and lift capabilities make the machines perfect for large construction projects.
Cranes have been around in one form or another since the time of the pyramids. Heavy lifting has been possible throughout the world due, in part, to the crane. The crawler crane has proved to be very versatile and useful on all types of ground and in all types of weather.