In some cases it is not feasible to use the edges of the inspection pit nor to modify them to suit the BM CLS type A version (cassette version). Therefore, BM has developed a pattern protected CLS version, where the rails are installed into the floor of the inspection pit and changed the cassette design into a (roller) skate design.
The BM CLS pit floor rails consist of two I-section steel beams, installed on the inspection pit floor. The length of these I-steel beams is made to customer specification, however, BM recommends a minimum working length of 7 metres, effectively allowing positioning of the CLS chassis claws 3 meters on either side of the brake tester. Hereby a majority of axle combinations of vehicles can be tested without the operator having to leave the vehicle cabin between each axle brake test.
During installation, the anchoring I-beams are concreted into the floor of the inspection pit. The actual rail is then made, by welding another I-beam directly onto these anchor beams. Finally, the CLS skates are easily installed onto this top I-beam. Hydraulic rams are fitted to the skates and connected to the vehicle chassis via chains and BM CLS claws. The hydraulic hoses are managed using traditional "energy chains" placed inside the I-beams, which protects the hoses from damages and also prevents the hoses from becoming a trip hazard for the operator.
The design of the CLS skates was improved in 2010 by developing a special "spring coil", which is mounted around the cylinder in the bottom. The benefit of this solution is that the hydraulic cylinder stays vertical at all times instead of "falling" to either side, when load is not applied. It can thus be avoided that the cylinder hits items placed on the inspection wall while the vehicle is being moved forward.
The operator controls the BM CLS type D system from the remote control unit exactly the same way as described for type A.
The BM CLS type D has the disadvantage, though, that the rail is installed onto the pit floor. However, most customers learn to value this rail solution, as when stepping up on the rail the operator can reach higher while working on the vehicle from beneath including placing the CLS claws to the chassis.