# Quadruplex upgrades



## bille1906 (May 2, 2009)

I have some spare time on my hands this week so I thought I would share what I have been doing with my Quadruplex.
For those of you who haven't seen the build it can be found in the "Informative Threads" section. 
When I designed the Quad, I made some decisions which made sense at the time. 
As I had four engines to control, I felt I needed something that would be easy to RC.
I decided to go with Ruby type reversers which would both control speed and direction.
This necessitated using piston valves.
I decided to use similar boiler and burners to the Cab Forward.
The engine ran smoothly with good power and was easy to control but I soon found some things I was not happy with
The piston valves had some leakage and the simple valve gear caused it to use a lot of steam.
I later found that the Cab Forwards are close to pushing the limit on the boiler with the two burner tubes.
I tried different jets to get more heat but I found that Quad boiler are only about 60% as long as the Cab Forwards and thus have less heating surface and the extra heat was going into the smoke box and causing heating damage to surrounding parts 
I decided to make two major changes

1. Convert the boilers to locomotive type with butane fired ceramic burners
2. Convert the engines to D valves with Walschaerts linkage

I started with the boilers

I wasn't quite sure how to get the innards out and wanted to use the original tubes with the fittings and bushings which lined up with the existing wraps
I decided to go with a dremmel and a cutoff blade to rough it out 








Once the core was removed I had a pretty rough tube to work with








I mounted a pattern making bit on the router table. The ball bearing rides on the inside of the tube and the cutter removes the excess material









The light reflecting off the sharp edge of the cut makes it look like it id deeper than the tube but it is within.001 of the edge








The slit is cut on the table saw with the blade as high as possible without hitting the top side of the boiler. the masking tape tells me where to stop








the side cut is done on the band saw








The shallow firebox is trimmed on the table saw








The throat and end plates are made and then drilled together. the tubes are slipped into the end plate and the throat plate is soldered on








Te backheads and crown sheets are fitted for soldering. You can see how the rear superheater loops around inside the firebox and comes out to the left of the door

















A firebox door is made for inspecting the burner








and mounted for bench testing








The front superheater id fed through the larger flue









The boilers are mounted on the chassis








They are painted and the boiler wraps are installed









Tomorrow, I will post photos of the ceramic burner process


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## bille1906 (May 2, 2009)

Ceramic burners have been used for years but mostly in vertical boilers.
I needed to go with ceramic as because of the drivers being under the fire box, alcohol was not an option because there would not be enough room between the wicks and the crown sheet and with two boilers to feed and the configuration, coal was not an option.

My friend built a Dee and his ceramic burner worked very well. I decider to use that design but go with a larger element. My first trys were with the larger element and one jet but I found that it was not enough gas to get a good burn. I tried larger jets but they didn't burn well and were hard to light so I decided to go with dual .008" jets
The element below was designed to be surrounded with air holes as the Dee has an air hole in it's design 









The ceramic burner needs standoffs to distribute the gas flow. I started with two square ones as shown below 









After bench testing, I ended up with the design below.
I then tested this design in a boiler and found that rather than the system gathering air from the holes, it was actually shooting flames out of them
I had built a choke to adjust the air flow through the holes and the final design is with them closed off completely 










Here is the burner on the bench test









And here is a look at it in the boiler 









I track tested the new boilers and the steam production was better than the poker burner design and it burns much quieter.
The heat in the smoke box and out the stack is greatly reduced.
I haven't had the chance for extended testing as I needed to change the position of the servos because most of the heat is now in the firebox area
so I decided to go ahead with the cylinder conversion and redo the reversing servos.


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## bille1906 (May 2, 2009)

On the cylinder upgrades, I struggled on the decision to go through the extensive effort for something that would probably not make a dramatic difference but I finally decided that the quad was just too nice to not try to make it perfect.
One day, I was air testing one of my Uintah chassis which is full Wlaschaerts and it was running so smooth, I decided to test It against a quad chassis. The difference was dramatic. 
This sealed the deal, I was going for it. 

I started by sketching out my design for converting from piston to D valves. I wanted to use as much of the existing parts as posible but I would need new cylinders and valves 









The cylinders were cut from !" square stock and turned in the four jaw. This shot shows the boring process. I start with a 1/4" pilot hole and progress up to 31/64" and finish with a 1/2" reamer. You can see how nice the table saw cuts the un drilled pieces. only a skim cut is needed on the lathe










The ports are drilled and milled 









The slide valve and nut are machined










Here are the parts ready to go together. The steel colored parts are from the original and the brass are new










The "T" is for the exhaust, the cylinder drains and cam lever are from the original.
The SS screw and spacer will keep the frame somewhat insulated from the cylinders








The 5/32" exhaust T slides on to 1/8" pipes which are press fitted and loctite'd to the cylinders. A round cross member is added for support as the prior cylinder assemble also was used as a frame support. 









The high pressure T needed to be steam tight so I made this design using 5 mm o-rings.
I like metric o-rings for fittings as they are thinner than standard ones 























Here it is in place. This design allows for one cylinder to be removed without the other being touched 










The Quad had an outside eccentric crank and a lever which resembled an expansion link and kept the rods parallel but did not do any reversing 
Because of the fire boxes, I could only put the expansion link in one place and it had to me smaller than it normally would be and slightly lower. Not much room for error
I made this box frame which is similar to the one I made for the Uintah. It slips over the drivers and properly positions the link
It also serves as the rear mounting bracket for the cross head slides. 









The cross head needed to be revamped for the working combination lever. If I were making new cross heads, they would have a drop link
incorporated in to the design but here I had to figure out a way to have a drop ling which did not swivel and had the attachment point where the slide rail was 








I milled out this link. The square part goes in the slot where the bolts are and that will keep it rigid








Here it is in place. You can see why I couldn't just attach the other link to the bottom of the cross head








This is what I started with.Not bad looking but non functional









Here is the finished result, full Walschaerts with working combination lever. The reversing arm on the top is controlled by a servo which is connected to a lever which drops down between the frames from the bar connecting the two arms (not shown in this picture)








I have bench tested these engines and they run considerably better than before the mod
They are back together in the quad and ready for track test whenever I get the chance to go for it


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## Semper Vaporo (Jan 2, 2008)

To have built the Quadraplex in the first place pretty much blew my mind, but to undertake such an upgrade and do such beautiful work is just beyond my ability to express my envy!


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## bille1906 (May 2, 2009)

Semper 
Thank you for your kind words


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## Phippsburg Eric (Jan 10, 2008)

very interesting project Bill!!! It is somewhat terrifying to attack an existing model with this kind of re-build! I hope and trust it will work well for you!


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## placitassteam (Jan 2, 2008)

WOW!!! Your work continues to amaze me. Thanks for posting.


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## xo18thfa (Jan 2, 2008)

Great work on those boilers Bill. Some real brain surgery work. Can't wait to see the Quad running at Sac next summer.

There is always controversy about setting up the Walschaerts gear. Bill's modification is correct and the way it should be done. The slightly offset pivots on the top of the combination lever is what makes the Walschaerts gear work. Without the offset pivots the running gear is just a gloried eccentric. 


Bob


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## Alan in Adirondacks (Jan 2, 2008)

Bill, 

Beautiful work as usual. Most impressive! 

Best regards, 

Alan


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