A closer view of one of the roller beams and v-groove cast iron roller bearing wheels, showing the blocking and bolts that support the wheels. The wheels roll on 40x40 galvanised angle iron (with the right angle pointing up) that has been spot welded to a length of 100x5 galvanised plate (actually, it was all galvanised after the welding was done). Note that there are metal plates at each end of the bolts to provide rigid support for the bolts which act as axles for the wheels. Also note some temporary wooden blocks used to support the beams during construction.