In 1929, the Bernina Railway addressed the locomotive's reliability problem by converting it from a C-C wheel arrangement into a B-B configuration, and therefore reclassified it as a Ge 4/4 type locomotive.
 The conversion involved removing the central axle of each bogie, lowering the traction motors, and installing new drive rods.
 These measures permanently eliminated the previous operational disturbances.
 At the same time, power output was able to be increased from 705 kilowatts (945 hp) to 760 kilowatts (1,020 hp), but this involved lowering the top speed from 50 kilometres per hour (31 mph) to 45 kilometres per hour (28 mph).

As a special feature, the locomotive had been fitted with a two axle subframe supporting the brake frame for the electromagnetic rail brakes, which were supplied with current through the overhead catenary.
 Due to these subframes, the locomotive's wheel arrangement is correctly described as C′2′C′ in its original form, and B′2′B′ in its modified form.
 The two axle subframe, together with a small luggage compartment, has never been taken into account in the official classification of the locomotive.
 Strictly speaking, the locomotive should be classified as GDe 4/6 in its present configuration.
In 1929, the Bernina Railway addressed the locomotive's reliability problem by converting it from a C-C wheel arrangement into a B-B configuration, and therefore reclassified it as a Ge 4/4 type locomotive.  The conversion involved removing the central axle of each bogie, lowering the traction motors, and installing new drive rods.  These measures permanently eliminated the previous operational disturbances.  At the same time, power output was able to be increased from 705 kilowatts (945 hp) to 760 kilowatts (1,020 hp), but this involved lowering the top speed from 50 kilometres per hour (31 mph) to 45 kilometres per hour (28 mph).
As a special feature, the locomotive had been fitted with a two axle subframe supporting the brake frame for the electromagnetic rail brakes, which were supplied with current through the overhead catenary.  Due to these subframes, the locomotive's wheel arrangement is correctly described as C′2′C′ in its original form, and B′2′B′ in its modified form.  The two axle subframe, together with a small luggage compartment, has never been taken into account in the official classification of the locomotive.  Strictly speaking, the locomotive should be classified as GDe 4/6 in its present configuration.
Bernina Railway Ge 6/6 81