opposing edges 101 of the hatch opening not only serve to support the oil tight covering 111 but also serve as rails for the longitudinally traveling platform according to another aspect of the invention each set of opposing edges 101 of different hatches are coupled with connecting rails so that the longitudinally traveling platform 102 can be moved throughout the entire length of the hatch compartments longitudinally of the carrier more particularly the longitudinally traveling platform 102 can be moved on the edges 101 that is on the rails of the hatch openings and the connecting rails 112 with the laterally traveling platform being carried thereon the longitudinally traveling platform 102 is provided with four wheels at the underside of the square frame thereof and can be driven by means of a diesel engine or the like the most important feature of the longitudinally traveling platform is that it can be removed as required the laterally traveling platform 103 can be moved laterally of the carrier on rails provided on the longitudinally traveling platform 102 with the supporting or outer cylinder 104 being mounted thereon and also may be driven by a diesel engine or the like and it too is provided with four wheels on the underside thereof like the longitudinally traveling platform 102 the laterally traveling platform 103 can also be removed from the longitudinally traveling platform 102 as desired the supporting or outer cylinder 104 supports the extensible inner cylinder 105 and maintains the inner cylinder 105 extended into the.