Heisler Overall Design
Many times when building the Shay I wished I had know about and understood some of the features and options I had to squeeze in later. Hopefully I'll do some planning this time and things should work out better. The following is a list in random order of items of concern and data relating to the items.
Water Tank: The Shay water tank at ~ 7.5 gal could be larger. The Heisler is 50% larger so we want at least 50% more capacity or at least 11.25 gal. The 13 gal tank in drawing above is about as large as we can make without deviating from the Heisler profile. There is no plan for a hand pump in the tender so the design will be a little simpler, just one low pressure feed pipe from the tender to the locomotive. A quick connect hose fitting like that used on the Shay will probably be used.
Axel Pump-Feed Water Heater: The plan is to use an axel pump to supply feed water via a feed water heater. The pump will be mounted on the front truck and feed up through the saddle to the heater located in the top of the smoke box. The heater output will feed a check valve on the right side of the boiler. There will be be an output bypass with valve to regulate the amount of water fed to the boiler. The valve is a fireman's control and thus will be located on the left side of the cab.
Injector: The locomotive will be equipped with a feed water injector. The injector will be located on the left side of the locomotive. The prototype had the injector in the cab against the left side of the boiler. That is one possibility for the model. Another possibility is below the cab floor on the left side. The steam and water control valves will both be on the left side of the cab.
Fuel: The locomotive will be fueled with oil as is MRSR 91.
Burner: The burner design will be similar to that used on the shay. A regulator will be used on the atomizer feed like was done on the shay. On the shay it was found that the blower needed frequent adjustment as the boiler pressure fluctuated. Failure to make these adjustments is probably the major cause of soot buildup in the tubes I'm going to try a blower regulator on the Heisler to see if that helps. The atomizer and blower controls as well as the fuel control will be on the left side of the cab. The plan is to try some different nozzle configurations in test setups to see if a better way can be found to mix the air with the fuel and minimize wasted input air. The final design may or may not include a adjustable air damper. I also want to try heating the atomizer and fuel feed pipes by running them inside the fire pan on the way to the nozzle.
Spark Plug: The burner will be equipped with a spark plug to relight the burner. The same design electronic circuit and 6 volt motorcycle coil used in the used in the Shay will be used here. The coil is 5.5" long and the largest diameter (a ridge on one end) is 1.875". The coil with electronic circuit will fit in the space between the fuel tank bottom and the top of the middle truck frame bolster.
Lights: I'll probably use the same 12 volt - 20 watt halogen bulbs Dick McCloy has been using on his locomotives. Dick connects them directly to 12 volt for the bright setting connects two lamps in series for dim setting. The dim setting is still very bright so running at 9 or 10 volts is probably more then adequate and a dimmer circuit is probably required. Instrument lighting is also required for the water glass and steam pressure gauge.
Battery: I didn't plan ahead for a battery on the shay so my options were limited when I finally figured out I needed electrical power. I ended up using a set of four D Cells on the shay. LEDs were used in the headlamps to keep the power drain low. This time I want to brute force the electrical supply so have decided on a 12 volt lead acid battery. A battery capacity of 10 to 20 Amp Hours would be useful if I run a lot at night. I found a 12 V, 17 AH sealed lead acid battery that can be used upright or on it's side. The battery dimensions are 7.13" X 2.99" X 6.54" The bottom of the fuel tank will be 3.25" above the bolster to allow room for one of these batteries above the bolster between the frame sides. There is also room for the electronic circuit and coil to one side of the battery. A solid state regulator will be required to reduce the 12 volts to the maximum 6 volts permitted on the electronic circuit and coil. There is also room in this area for a light dimmer regulator. The electrical circuit will be equipped with a voltmeter to indicate charge.
Electrical Switches: The electrical switches for lights will be located under the cab on whichever side has room.
Battery Charger: The battery charger will either be external or located under the fuel tank if there is room. A jack for either charger input if the charger is mounted on the locomotive or charger output if the charger is external will be mounted somewhere on the underside of the cab.
Oil Tank: The Shay oil tank is ~ 2.25 gal and adequate ---- the water tanker must be filled several times for each tank of fuel. The Heisler fuel tank shown in the drawing above will be ~ 3.4 gal which is 50% bigger than the shay tank and also adequate. It would be nice to have an easy way to tell the level of the fuel tank. The prototype had a fairly large opening to fill the tank. If that type of an opening is used it may be possible to judge the fuel level through the opening. The tank will need to be removed easily to access the equipment underneath. The shay used only two screws to hold down the fuel tank, accessed from underneath near the outer edge. That should be adequate for the Heisler too. An additional 2 to 4 small screws may be needed to secure the top rear of the cab side to the tank. It may be possible to have some sort of a sliding fastener in that area and avoid the need for the screws.
Fuel Filter: The fuel line to the nozzle will require a filter. The rather course one used on the shay is probably the best choice. The filter is located under the cab floor on the shay and rather difficult to get at. A better solution for the Heisler might be to locate it between the frame side and the frame side channel. Also, the filter should be easily removed for cleaning ----- maybe a sort of quick connect similar to that used on the shay water lines might work.
Fuel Valve: The fuel valve on the shay is an inexpensive needle valve located in the inside bottom of the tank and controlled by a shaft running up through the tank. For the Heisler I prefer a better quality needle valve possibly located below the cab floor between the tank and the the back of the boiler. One possibility is to have a fuel shutoff valve below the tank and fastened to the tank bottom. The output from the valve could feed the filter through a quick connect and then on to the control valve via another quick connect. One of the filter quick connects could be opened to provide a path to drain the tank if necessary. The quick connect would also make it easier to remove the tank if necessary to access the stuff under the tank.
Compressed Air: A small manifold will be provided to supply air or steam to the atomizer and blower regulators. A standard air quick connect will be provided on the left side under the cab floor with check valve and shutoff valve to supply air to this manifold during startup. There will also be a steam line from the turret (with valve) to the manifold to take over from the air supply once steam pressure has built. The steam valve will be closed during startup to keep air out of the boiler.
Foot Pegs: Folding motorcycle type fool pegs will be attached to the frame side channels near the cab doors.
Whistle: The locomotive will be equipped with a steam whistle similar to the one described in SO YOU WANT TO BUILD A LIVE STEAM LOCOMOTIVE. That whistle is 1.5" diameter and 12" long. The whistle will be mounted under the fuel tank or cab floor between the frame side and the frame side channel Experience with the shay is that after adjusted initially, the whistle requires no maintenance. The channel is also 1.5" high so the whistle can be mounted on the inside of the channel U where it will be completely hidden. The whistle valve will be located on the right side of the cab.
Air Brakes: The locomotive will be equipped with a two stage steam powered air compressor mounted above the right side of the front truck. There will be one or two air storage tanks under the boiler behind the saddle. There will be a regulator in the air line feeding the brake valve. The brake valve will be located on the right side of the cab. Single acting brake cylinders with spring return will be used the front and tender trucks. The middle truck might be too crowded for the brake hardware. The tender truck will be equipped with a park brake.
Cab Roof: The shay roof was arranged to be raised when operating and lowered for show. That arrangement worked OK but in many cases I just removed it to make operation easier. The center of the Heisler roof will be open from the back most of the way to the front and be permanently attached.
Remote Controls: The most frequent used controls on the Shay are the throttle and the blower. Hopefully, the planned blower regulator will eliminate the need for that constant adjustment. The engineer must bend over to reach the throttle on the shay which can lead to a sore back. Bending over and reaching for the throttle also causes the engineer to take his eye off the track ahead. The plan for the Heisler is to mechanically link the throttle, reverse and brake controls to levers on top the fuel tank behind the cab roof. These levers should be high enough so that the engineer can make adjustments without bending over. The remotes should be made easily removed to restore the aesthetics. Maybe a remote for the whistle valve would also be nice.
Steam Turret: The steam turret will be fed from the steam dome with a pipe that runs along the top of the boiler into the cab. There will be a ball valve is this pipe to isolate the turret from the boiler. The turret will be a square horizontal brass bar the runs cross ways on top the boiler near the back. Angle control valves will screw into the cab side of the turret. The following control valves will be required:
The injector might use a handle type valve like the type made by LSM rather than the angle valve.
More to come later.