Where is the pressure in the main reservoir indicated?

The pressure in the main reservoir is typically indicated on a gauge under the car. This is because the pressure measurement needs to be taken directly from the location of the reservoir, which is designed to provide an accurate reading of the compressed air pressure used for various systems within the train, including braking and other pneumatic systems. Gauges are placed strategically to ensure that the train operators can monitor these critical measurements without compromising safety or operational efficiency.

While the engine panel, conductor's cabin display, or dashboard of the locomotive may show various operational data, direct readings from gauges located close to the components they monitor provide the most reliable and immediate pressure information. This design focuses on operational safety, ensuring that the train operators can access vital metrics directly from the source.