Gantry crane used several factors to be considered

Span and boom length
Span  overhead gantry crane  itself is affecting the quality of the important factors. Selection, to meet the conditions of use and equipment conform span series of standards under the premise of the span should be minimized.
Principle for determining Tread
(A) to meet the  gantry crane  rails along the direction of stability requirements (b) the dimensions of the goods to be able to pass the legs flat steel frame (c) pay attention to the track B and the span S proportional relationships, and generally round from B = (1/4-1/6) S.
Gantry crane pitch size determination
At work, gantry cranes and yard external dimensions of goods and transport vehicles between channels should leave some space dimensions, in order to facilitate loading and unloading operations. General transport vehicles in the span of loading and unloading, should be kept above the door legs with 0.7m spacing. Spreader should not work with the transport vehicles with more than 0.5m spacing, cargo interlude legs, there should be more than 0.5m spacing.
Gantry crane electrical equipment used
It should meet the common  bridge gantry crane  GB/T14406-1993 the relevant provisions.
Single girder and double girder gantry crane used
Under normal circumstances, from the weight of 50t or less, in the span of less than 35m, no special requirements, should use a single main beam. If you require a large gate leg width, high working speed, or frequently lifting heavy pieces, grew up pieces, you should choose double girder gantry crane.