The use of a square drive interface between a wiper arm and its motor or linkage shaft has proven to be advantageous on numerous modern OEM railway applications. They provide an ability to fit the arm in the correct park position first time every time and are also significantly more resilient to the problems of spinning on the traditional tapered DIN spline interface as a result of bird strikes and/or inconsistent fitment standards. As a result of this a number of operators have identified that the benefit can be read across by retrofit to older vehicles by changing the relevant components to the new design.
Many of the older vehicles were built with either a pneumatic BPM wiper motor or an electric wiper motor system that was coupled via a linkage system to its stainless steel output shaft through the bulkhead and onto the DIN taper spline wiper arm. It will be seen from the adjacent illustration that the process of changing the DIN taper swivel shaft is a simple substitution of one for the other to upgrade to the square drive swivel shaft.

In cases where the wiper arm is of an arcuate type the changing of the swivel shaft and the fitment of a corresponding arcuate wiper arm is all that is required. If however the vehicle is fitted with a pantograph wiper arm then in addition it will also be necessary to substitute a new slave arm swivel post in place of the existing swivel post as illustrated by the corresponding leaflet.

DIN Tapered Spline
Square Drive
Class/
Type
Manf.
DIN Taper
Swivel
Shaft
Driver's Side Square Drive
Swivel Shaft
Assistant's
Side
Square Drive
Swivel Shaft
165
BREL
534257
M401942
M401942
166
BREL
534257
M401942
M401942
323
HUNSLET
534270
M411510
M411509
325
ABB
M400488
M402102
M402103
365
ABB
M400488
M402104
M402105
442
BREL
M401861
M402106
M402107
465
MCL
534270
M402108
M402109
465/1
BREL
534540
M402110
M402111
465/2
BREL
534540
M402112
M402113
466
MCL
534270
M402114
M402115
IC3
ABB
M400817
M402116
M402117