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Trouble Shooting


When Aster locomotives are in good operating condition, properly lubricated, provided with distilled water for the boiler, a good grade of fuel for the burner and steam cylinder oil, they will perform as follows:


  1. They can pull their maximum load, at a constant speed, for several hundred meters.  Some models such as the BR-86 are capable of making runs of over 3/4 of a mile while hauling a heavy load on a level track

  2. Their exhaust beat is strong and regular.

  3. They operate equally well in either forward or reverse.


If a locomotive's performance has deteriorated, this is no cause for alarm since minor maintenance will usually restore the original capabilities. 


Typical problems and remedies are given below.

Steam Generation Problems

If it takes more than five to 10 minutes to generate "pop-off" steam pressure in an alcohol fired locomotive which is properly filled with distilled water, proceed as follows:


(1)  Check the fuel supply for contamination.  Uncontaminated fuel will burn predominately blue.  Contaminated fuel burns predominately yellow and should be replaced.


(2)  Check the condition of the burner wicks.  Replace them if they are burned and hardened.  New wick should extend5 to 6 mm from the top of the tube and should not be tightly packed or twisted in the tube.  Fluff the top of the wicks


(3)  If the problem still exists, check to see that there is proper draft as follows:

a.  Does the suction fan provide sufficient draft?  Some Aster locomotives, such as the Pannier, require a strong draft and a homemade fan may not be powerful enough to do the job.  Use an Aster fan and fresh batteries.

b.  Are the battery leads connected to the suction fan correctly so that the fan is pulling air through the fire box and is now blowing air into the smokebox?

(4)  If the suction fan raises pressure but the locomotive's blower system is not able to maintain it, check the following:

a.  Is the blower pipe nozzle blocked?

b.  Is the blower pipe positioned so that the nozzle discharges directly up the smoke stack?

c.  Is the smoke box door sealed?

d.  Is the lining inside the fire box and boiler intact?

e.  Is the fire box throat blocked?

(5)  Replace the pilot wick on vaporizing burners.  If the main burner still does not burn properly, replace the main wick and clean the pin holes in the main burner.


Remember, a forced draft boiler ALWAYS requires a draft.  A suction fan is necessary when first raising steam otherwise, the fire will not light.  Once steam is raised, the locomotive's blower must be cracked open to maintain the draft when the locomotive is stopped.  During the run, the exhaust provides the draft to keep the fire burning

Steam Leakage

If the locomotive will not move and a continuous steam flow comes from the smoke stack after the regulator is opened, the slide valves may not be in contact with the valve face.  Gently tap each slide valve cover plate and open the regulator.


If the problem persists, removed the cover plates and inspect the valves.  Removed any foreign mater, including surplus sealing compound, and check the valves for proper timing.  If the slide valves still do not seat properly, it may be necessary to file the valve block opening slightly so that the valve block is a slip fit in the valve and the valve rest squarely on its face.  Refer to the appropriate assembly instructions for details.


Check the steam lines from the regulator to the cylinders to be sure there are no loose fittings which are causing the leak.


Worn piston rings or dried packing can also cause steam leakage.  If the pistons slide very easily, without some drag, this may be the problem.  Removed the cylinder heads and check.  The solution is to replace the rings or packing per the appropriate assembly instruction.


Steam leaks can sometimes be seen coming from the gland nuts on the slide valves and cylinder back heads.  Tighten the adjustment nuts and see if the problem persists.  If the leak is excessive, repack the the glands per the appropriate assembly instructions.  It is normal for these glands to have slight steam leaks after the locomotive has been broken in.


Be sure that there are no burrs on the rods which will catch and damage the packing.  Graphite yarn, used for packing some glands, is made of cotton string treated with oil and graphite.  It will last several years before requiring replacement.  The gaskets used to seal the valve covers and cylinder heads are made of paper and can be easily duplicated by cutting them from a long fiber type paper.  The packing compound is silicone sealant which is available at most hardware stores.  When repacking or resealing any component, refer to the appropriate assembly instruction for detailed instructions for detailed information. Always be careful not to use an excessive amount of sealant since it can plug steam and water passages. 

Check Valves and Water Pumps 

Slight leakage in the check valve or feed water pump can be ignored so long as the pump operates satisfactorily.  Check valve balls occasionally stick shut and can sometimes be freed by tapping the valve body with a small wrench or by topping off the water supply and pumping vigorously for several strokes.  If the ball remains stuck, remove the check valve plug and pry loose the ball using a small screwdriver.  Clean the inside of the valve body, paying special attention to the seat, and replace the ball with a new one.  Add a small amount of packing compound to the threads of the check valve plug before installing it, being careful not to let any get inside the valve body.  Water pumps should be fitted with new O rings if they cannot deliver water to the boiler when it it at working pressure.  Refer to the appropriate assembly instructions for the correct procedure.

Valve Setting

If the locomotive does not operate properly and there is an adequate supply of steam and no excessive leaks, it is possible that the valve timing has been disturbed.  Each locomotive has specific instructions for properly setting the valves but a few general comments will be given here.


First, compare the relative positions of the wheels, rods and valve gear with the drawings in the assembly instructions to see if things look approximately correct.  If they do not, inspect the mechanism to see if a loose screw has allowed a crank or eccentric to slip; correct as required.  If a crank pin has become loose in a wheel and rotated, it will be necessary to remove the wheel assembly and twist the crank pin into its proper position per the assembly instructions.  Next drill a small hole through the base of the pin and wheel.  A small drift pin can be pressed into place which will lock the pin to the wheel in the correct position.


When the piston is at front dead center and the valve gear set for forward running, the edge of the slide valve should be just beginning to uncover the forward steam port.  Figure 46 shows the correct relative position of a Walschaert valve gear while Figure 47 shows the gear incorrectly set.  Be sure that the lifting arms of the Walschaerts valve gear are correctly aligned otherwise the radius rods will be incorrectly positioned. 


Figure 46: Walschaert Valve Gear Correctly Set


Figure 47: Walschaert Valve Gear Incorrectly Set


After setting the valves, ideally the valve ports will be opened equally in both forward and reverse running.  Some times tolerance buildups do not permit this and if it cannot be achieved, set the valves so that in the forward running position, the ports are equally opened.  It is not necessary that each port be completely opened. 

Fuel Leaks (Alcohol)

If a wick type burner overflows and spills alcohol out of the wick tubes check the following points:

(1) The filler plug is not properly installed.  Check to see that the O-ring is in good condition.


(2) The bottom end of the air pipe, shown in Figure 40, does not extend down far enough in the sump.  Remove the sump and extend the length of the air pipe by slipping a piece of silicone tubing over it



(3) If the top end of the air pipe is below the lower edge of the filler plug fitting and the tank is overfilled, fuel will seep down the air pipe and flood the sump causing the excess fuel to spill out through the wicks.  Remove fuel until the over flow stops and when re-filling use the exact amount of fuel specified.


(4) On a hot day, a tank locomotive, such as the Pannier, may have its fuel supply start to vaporize because of the proximity of the fuel tank to the burner.  This may cause fuel spillage and fires along the track.  Halt operations and close the fuel needle valve if this occurs.  Cool the top of the fuel tank with a wet cloth and do not resume operation until the ambient temperature is cooler.

Remember, the the level of fuel in the sump will normally coincide with the lower end of the air pipe.  This level must be below the top of the wick tubes or else  fuel leakage will occur.  If a vaporizing burner pilot wick overflows, the fuel tank needle valve is opened too far.  Open it to the point that fuel flow equals burn.

Marine Engines and Shay Geared Locomotives
The same general instructions which apply other Aster locomotives also apply to marine engines and Shay locomotives.  These engines are fitted with Stephenson valve gear, as show in Figure 27. 

Figure 27: Stephenson Valve Gear


Operational problems are usually the result of the valve gear retaining screws loosening which disturbs the valve timing.  The appropriate assembly instructions contain detailed information for proper valve setting.  The use of a thread locker, such Loctite 222 or an equivalent, will prevent the problem for recurring.   If steam is exhausted from the blast pipe, when the regulator is opened but the engine is stalled, the piston packing may be in need or replacement.  Refer to the trouble shooting instructions concerning steam leakage. 


The test bench rollers and stand is a convenient accessory for testing locomotives under steam if a track is not available.  The drive wheels are set on the rollers, while the lead trucks and tender wheels are set of support.  The stops holds the locomotive in position.





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