Windscreen Wipers
As with any vehicle with windscreens, trams require windscreen wipers to enable the driver to see through the windscreen in wet or snowy conditions. The earliest versions of wipers were spring-loaded and operated manually by the driver. Later versions were operated by bleeding a small amount of compressed air, via a small pipe, off the air brake system. Normally the control for the air operated windscreen wipers was a small valve located on the wiper mechanism, with the speed of the wiper controlled by the amount of compressed air allowed into the wiper mechanism. Modern trams that do not have air brake systems instead use small electric motors to operate the wipers. The control switch for electric wipers will generally be found on the driver's console.
The fronts of very early trams were open to the elements and did not have windscreens. However all modern trams have enclosed fronts.
Read more about this topic: Tram Controls