Another idea--new gauges for steam locomotives:
1.
BACK PRESSURE GAUGE: Not all locomotives have them, but when so equipped, they assist the engineer in choosing the right cutoff setting. Back in the day, the recommended back pressure was about 6-14 psi when the loco was in operation. Unlike steam chest pressure gauges, which measure the steam pressure on the
intake side of the valves, back pressure gauges measure the pressure on the
exhaust side of the valve. Since the extended HUD already has a readout for back pressure, this can be easily implemented.
2.
RECEIVER PRESSURE GAUGE: On compound locomotives, these measure the steam pressure in the receiver pipe (between the high and low pressure cylinders) and help the engineer determine whether the engine is working either simple or compound. Usually, engineers made the switch from simple to compound when the receiver pipe pressure reached 70-80 psi (unless the loco was fitted with an automatic intercepting valve).
3.
PYROMETER: Most commonly found on superheated locomotives, the pyrometer measures the temperature of the incoming superheated steam to the steam chest. The pyrometer provides a more accurate and instantaneous indication of locomotive performance, as it is much more responsive to water and fire conditions that lower the total superheat. When the engine is in operation, and the throttle is wide open, the pyrometer should give a reading equal to (based on the information provided by the extended HUD): (Water Temp + Max Superheat) * Throttle Opening. Anything lower than this is an indication of either priming, foaming, a bad fire condition or other adverse conditions that affect locomotive performance.
(Side Note: On locomotives equipped with front-end (smokebox) throttles, the "Maximum Superheat" and "Current Superheat" should ideally be the exact same value at all times, regardless of throttle opening percentage, since the superheater elements are always filled with steam. Since the pyrometer measures the temperature of the steam at the steam chest, only the pyrometer value should fluctuate with throttle opening.)
4.
STOKER STEAM GAUGE(S): On locomotives equipped with mechanical stokers, there were two or more pressure gauges, one showing the pressure of the steam being delivered to the stoker engine (indicating the feed rate of the stoker), and two or more gauges showing the pressure of the steam at the distributor steam jets (which help spread the coal over the entire grate area).
Also, an improvement to tender water gauges--it would be nice to specify the calibration of the tender water gauge as a height unit (inches, cm, etc.) instead of a volume unit. Most tender water gauges are calibrated in the height of the water level above the tender bottom, especially when the tender water tank is an irregular shape.
Here is an example PRR tender diagram that shows the correlation between water height and volume.
cesarbl, on 06 July 2023 - 06:31 AM, said:
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