MRSR 91 Burner
Nelson Riedel,
10/04/2004, last updated

Most locomotives in the eastern US were coal fired.  In the northwest US oil firing was very common if not prevalent.   Being from the Midwest, I'd never seen an oil fired locomotive before going to Mt Rainier Scenic Railroad.  In fact, I don't recall seeing any photos or drawings of the full size oil burners.    It turns out that the burner on MRSR 91 has many similarities with the oil burner on my Shay model,  ---- a design copied from Bob Reedy's Climax.    

The MRSR 91 burner is described below.  I didn't bother taking a bunch of measurements.  However, one should be able to estimate the dimensions based on the known size of nearby parts.

Fire Pan: This photo taken from the right side looking back shows the right front corner of the fire pan. The bottom of the fire pan is just above the top of the drive shaft.    The fire pan slides up inside the firebox.   The ash pans which hang down on each side of the drive shaft of a coal burner have been eliminated.   A couple stiffening angles run the length of the pan on each side of the drive shaft.   

The burner nozzle is directly above the universal.  The louvers control the burner air supply. 

The brown extension cord was being used for work lights and had nothing to do with the burner.

This shows the right rear corner of the fire pan partially hidden behind the right rear boiler mount..   The only opening in the fire pan is at the front as shown in the previous photo. 
Inside The Fire Box: This may be the most interesting photo of the bunch.   After seeing the grates of the coal burner I was curious as to the inside of of an oil burner firebox.  This is the view from the firebox door.   Those are probably firebricks lining the fire pan sides.   The horizontal slit in the burner nozzle is clearly visible.  That is a plastic soft drink bottle near the front.  I don't know whether it was placed there to help in the starting process or if the Heisler doubles as an incinerator.   
Firebox Door: The firebox door is a second source of draft for the burner.  The door is quite large to provide the air passage from near the floor up and into the firebox.  The lever on the side probably controls louvers to regulate the draft. 
This in the inside surface of the door.  That plate has holes to let the draft air pass while probably preventing flames from shooting out the door.  
Burner controls: This photo shows two of the three burner controls.  The upper handle controls the inner shaft of the column that links to the oil valve.  The lower lever controls the outer shaft that links to the draft louvers at the front of the firebox.   The third control is a valve that controls atomizing compressed air (during startup) or steam to the burner nozzle.  The knob just in front of the upper lever is probably for that valve.   
This shows the bottom end of the control column with levers attached to both the inner and out columns.  There is a link leading to the front connected to each link. 

The canister in the middle of the photo is connected to the oil line.  I suspect it contains a filter.

This shows the left front corner of the fire pan.  The long lever near the middle is attached to the oil valve.  If you check the previous photos you can trace the linkage back to that upper handle in the cab.  

The lever on the right side of the photo connects to the lower louver shaft.   The linkage to this lever can be traced on the previous photos back to the lower control handle in the cab.    

This is the right front corner of the fire pan where the two louver shafts are linked together.  
Lighting The Burner:  I was standing on the ground just outside the left cab door when they lit the burner.  

The first step was to connect compressed air and turn on the biggggg compressor.  Next, they soaked a couple rags with something and threw them in the firebox.  They then soaked another rag, lit it and threw it in the firebox.  The last step was to open the oil valve and adjust the air.   

Outside the door was a good position to take this photo and also to keep one's hair from being singed.  

Closing the door .......
This shows the atomized oil stream exiting the nozzle.  There appears to be something burning on the floor of the fire pan --- probably that plastic bottle.  

After the burner was on for a few minutes the fire at the end of the nozzle went out.  The crew made a few adjustments and it relit.  

Oil was dripping from the  nozzle onto the fire pan and dripping onto the ground.  That oil didn't catch fire. 

This photo taken from the right side gives a good view of the atomized fuel spray. It looks very similar the operation of the burner in my Shay ------- it even sounds similar which is reassuring.

The oil feed is via the bottom of the nozzle and the air/steam enters the forward side of the nozzle via the smaller pipe.  That is the blow down valve in the upper right corner of the photo.  

Smoke:  The oil burner seems to smoke about as much as the coal burners.  I noticed that the locomotive threw off huge clouds of black smoke occasionally on the scenic ride later in the day.  

I can make the oil burner on my shay smoke without difficulty.  However, I always associated smoke with soot in the tubes.  Maybe that needs a bit more research.  


Heisler Project
NLW Home