A razor cartridge has a housing having a guard and a cap and a plurality of parallel blades supported by the housing between the guard and the cap, each blade having a respective cutting edge. The annular main body portion has inner and outer diameters approximately equal to inner and outer diameters, respectively, of the plain end of the pipe. In a preferred embodiment, the abutment includes a tapered edge at the abutment surface to provide a space at the join in which a skim of plaster can be applied to provide a seamless join between the partition wall and the abutment. By receiving the non-common data identifier, one peer of the group may determine whether another peer of the group is sharing the same non-common data piece. A processor onboard each tramcar calculates the distance and time remaining to the next stop-boarding area.