of the filler blocks being approximately the same as the lengths of the respective sleeper blocks 33 if the grade difference between the roadways is constant over the length of a section the heights of the filler blocks at each end of the section will be the same if the grade difference between the roadways changes over the length of a section the heights of the filler blocks at each end of the section will be different this situation is illustrated in fig1 where the height of the filler block at the left end of the left hand section assembly 1 is u03b4 the height of the filler blocks at the interface between the two section assemblies is u03b4 u03b4 and the height of the filler block at the right end of the right hand section assembly is u03b4 u03b4 39 since the adjacent ends of successive section assemblies are set to the same difference in grade level between the two roadways it may be advantageous to provide a single filler block to support both adjacent ends the height of the second half section in the embodiment of fig1 3a is greater than the height of the first half section the height difference is selected to provide a suitable minimum height dimension for the filler panel 5 when the difference between the grade levels of the two roadways is zero fig3 b illustrates an assembly for this situation since the vertical offset is zero the.