[3] Another consideration was possibly that their bodywork usually required less heavy repairs than the older models in terms of rust and other damage, such as bent panels and frames.

The compressed air pipe is run through bolster and other members and then in a zig-zag pattern under the locomotive's belly to extend its length, which allows the maximum amount of moisture to condense on the way to the reservoirs.

A weakness of the system was that, after an accident or even a hard coupling, these pipes tended to develop leaks at the joints which were extremely difficult to repair.

Since this already increased the per-unit rebuilding cost, it was decided to simultaneously re-route the compressor pipe away from bolster and other members to the outside of the bodywork on the locomotive's right side, from below and to the right of the cab door to just before the second sandbox lid from the rear end.

With regenerative braking, the energy generated by the traction motors is dissipated by the resistor grid banks at the substations, when it is not absorbed by other locomotives in the same electrical section.

Since there was no guarantee that another train would be in the same section to absorb the regenerated energy, there was always the risk that line voltage could exceed 4.1 kV, which would make either the sub-station or the locomotive trip out.

With rheostatic braking, the energy generated by the traction motors is dissipated by the resistor grids on the locomotive itself.

[6] On the sides, obvious visual distinctions from the Class 6E1 are the left one of the two large grilles which was removed, with the opening filled in, two new large grilles which are installed in the centre lower sides to serve as air intakes for the rheostatic braking resistance blowers, and a large access door to one of the high-tension compartments, which is installed in place of the rightmost small window which was in the upper side of the Class 6E1.

[5] The locomotive is controlled via resistors over which the voltage is dropped in a configuration of series and parallel electrical circuits.

[7] Upon starting and in the low notches, the major part of the voltage is dropped over the banks of resistors and all four traction motors are in series.

As the driver notches up, some of the resistor banks are cut out via the pneumatically operated switches and the voltage increases across the traction motors.

[7] The locomotives in a consisted set are switched between series and parallel mode automatically, based on speed, overhead voltage and electromotive force (EMF).

[1][4] The Class 6E1 series lineage identification features, as well as the liveries which were applied to these locomotives, are illustrated in the following pictures.

Note the external compressed air pipe on the right side of locomotives rebuilt from Class 6E1, Series 6 and 7.