Abstract: A brake assembly for impeding the longitudinal travel of a moving object. The brake asembly provides for a biasing mechanism which biases an engagement block into the line of travel of the moving object. When the moving object contacts the block, movement is impeded until the object is subjected to a force capable of deflecting the block counter to the biasing member and out of the line of travel of the object. The object can thereafter move past the said brake assembly and continuing along its line of travel. In particular, the brake assembly is used to impede the longitudinal travel of a reciprocating sootblower until the cleaning nozzles of the sootblower have had their position indexed relative to a previous cleaning cycle.