I hate intermitten problems. I like it when I can pinpoint a reason for a failure. This is not happening with my Mallard.
For those of you who are unfamiliar with this system, the locomotive contains the controls, throttle, cylinders and lubricator. The tender contains the boiler. A high pressure hose carries steam from the boiler to the throttle/ reverser header. There are two electrical boxes, a transformer that plugs in to the wall and a controller that is fed from the transformer by a 4 wire heavy duty cable. Two wires go to the tracks. When power is switched on at the transformer box, the voltage applied to the tracks is set by moving a wheel to one of 4 positions. The highest position is called Super Heat and is used to bring the boiler temperature up quickly. The lowest is not actually a setting, but kind of like another off switch. There are two intermediate settings that are used when running. The throttle and reverser are combined in a momentary three position spring switch. The center position is the normal one and springs keep it there. Getting the loco to run one way or the other is accomplished by holding the switch for short periods of time against one side or the other. A small servo motor in the locomotive adjusts throttle position and reverser position. To stop, you must throw the switch to the opposite side and hold it there until your loco comes to a halt. Of course, I am simplifying, as there are may ways to get the engine to slow down.
Alarms sound when:
The loco is off the track and there is no load on the electrical circuit.
Water is gone from the boiler (a sensor )
When the alarm sounds, power is also cut from the throttle control box to the track. I have been having an issue where the alarm sounds when the loco is sitting on the termianl (power) track with water in the boiler. The voltmeter on the throttle box shows there is a load.
Last night, Luke obliged after I read him some stories and rocked him to sleep (and that is way more rewarding than anything I've ever done with a train by the way!). I went down to the basement and starting to tinker. FIrst, I replaced the seal on the boiler water fill plug. The old one didn't look too bad, but it was a little beat up, so it was probably good I replaced it.
Then, I tried steaming up. First was super heat. After 7 seconds, the alarm sounded. I tried a few other throttle settings and then, for an unknown reason, the alarm did not sound, and water was boiled. Once we reached operating pressure, as indicated by the safety release popping a few times, I slowly started running her. At first, she ran a little rough. Once the cylinders were warmed up and clear, she ran very well forward and backward. I was able to operate her with superheat settings, and almost no throttle, but I stopped after a short time because I feel this is hard on the engine. She ran for about 20 mintues, and I decided to go to bed, so I backed her carefully in to her siding and shut her down.
No idea as to why the loco will steam some times and not others.
The voltmeter showed me that maybe I need to do some more track work. Sitting on the terminal track, she drew 14 volts. Moving down the line a little bit, she was drawing 16-17 volts. No difference in throttle settings, either. The loop she runs on has 3 switches, two #6's back to back with the frogs on the same side and a #4 with the frog on the opposite side. It could very well be that I need to run a jumper around the switches. I did burn up Atals terminal tracks when I first tried running this engine. I can't imagine how many amps she pulls.
Any ideas welcome!! Direct combustion of coal, gas or alcohol is not an option! This is a plastic train! We use only the finest Nuclear or Dirty Coal (from Brunner's Island) generated electricity for this basement railroad!! Alcohol is reserved for the driver as this railroad operates on a bar. Besides, its a waste to burn good bourbon or single malt scotch. I geuss I should only be allowed to consume Single Malt scotch when running the likes of Mallard...
Thanks for letting this discussion of a smaller live steamer happen here. The horby live steam site is not as much fun.