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The PNG Short Passenger Car Kit

Update 3-15-2018

My trip to California is complete. Got the taxes done, played with the kids and grandkids and visited old friends. As all of you that have built a PNG kit know, a complete frame is included with all kits. It's far easier for me to create a perfectly square frame in my shop than to provide the customer with lumber and a jig and hope for the best.

So, for the short passenger cars, I start with a a 6" wide by 24" long sheet of 1/2" thick UHMW. This is the material most often used as cutting board.

A sheet of UHMW in the vise and getting drilled with a precision .250" drill. I only wish I had room in my shop for this big guy!! The 3 red circled holes are a goof. I read the wrong X & Y coordinates. I guess I'm human!!

 

All the holes drilled. In the left picture and a ball end mill is run across the width. This provides a slot for a screw driver to slide in under the frame and pop it off the jig easier. A few of the 1/4" Delrin pins needed knurling so I can pull them out easily.

 

I mount the UHMW on "white wood" 1" X 2" board. Not really sure what white wood is, some kind of southern pine I think, sold at Home Depot here in Colorado.

Here's my goof's. The 3 holes with red circles are .110" to close so I milled off .110" from one side of the 1/4" Delrin rod. The green peg on the top right is to correct a hole that was 1/8" to far away. So it's a 1/2" rod with one end turned on the lathe to 1/4". I have a dozen frame jigs for the various kits. I might have 2-3 without "fixes".  Hence, when producing a new kit, I call them the first cut, second cut and so on until I have it right. The other black circles are the tops of sheet rock screws that fasten the UHMW to the wood 1" X 2".

This is the CAD drawing with holes for the Delrin pegs.

Finished jig with pins inserted. The long groves about 1/4 of the way in on both sides are for a screwdriver to slide in under the glued and nailed frame to pop it off the pins and free of the jig.

I've also been drawing up the CAD for the coach. This is the master CAD that other pieces will be derived from.

To be perfectly clear about this kit, no narrow gauge railroad had short passenger equipment. This will be a freelance kit. The Sierra Railroad in California has a short coach and combine in standard gauge. They had them made for one of their branch lines that had exceptionally tight radius curves. Pictures of those 2 cars are on the previous page. As drawn, this kit will be 20" long from platform end beam to platform end beam. The real coach had 9 windows so I've done my best to represent that in this kit. I've also made the height and width the same as Accucraft's J&S coach so if they were run with the Accu cars, they would look the same only shorter.

Here's the end drawing of the coach.

I engineered the cars to use Kadee "E" type of couplers because they are the only coupler out there with enough swing to work with the cars on medium curves. The couplers are the number 906. I will order them from Kadee in the rust color to save us from having to paint them and possibly foul up any moving parts.

The cars are also engineered for the Aristocraft short passenger trucks. I have several cases of these trucks on hand and they were always planned to be incorporated in these cars.

Aristocraft Short Passenger Trucks

As compared to Accucraft J&S trucks.

I expect to have the frame jig completed in the next 30 days and will work on the CAD drawings that will drive the laser so we can get a look at how this will come together. I'm working with Bob Hartford for some 3D parts to use as masters for the roof ends and other white metal parts I don't currently manufacturer. In return for Bob's help, I'm supplying him with some of my PNG parts that he needs. Bob was here in late August and I walked him through my methodology in kit manufacturing and we compared ideas on several items. Always a good thing when we can work together!!

I did have one suggestion from a follower that thought maybe using Trackside Detail brass end handrails would be good. This will be a set of 4 cars. 2 coach, 1 combine and 1 baggage. Using TD's brass rails will add almost $100 to the cost of the 4 kits. What I think I may do is match the post holes in the end beam for the end rails with the same dimensions of the TD holes but supply white metal rails in the kits. If you decide to upgrade to brass, you may do so at your expense. I'm still chewing on seats. But I'm also trying hard to keep the cost in the $650-$700 range for the four kits. Everything I need, trucks, couplers, resin, wood, brass and white metal alloy keep getting more and more expensive.

More to follow .............. soon I hope. If you have any ideas or comments, feel free to shoot me an email. I am getting a little feedback and or questions. First of all, the Aristocraft trucks are not ball bearing and the way they are designed, there is no way to bearing them. But, they seem to roll fairly well. I don't think an electric or live steam engine will have any problem pulling 4 cars. Still chewing on any sort of interior.                                Phil    3-15-18

March 21, 2018

With the frame jig finished it's time to cut some wood and test it out.

A bunch of basswood sticks cut to length and laid into the jig. The platform end beam and the car body end beam had to be laser cut.

Doing this takes more time but is far stronger than if I cut short little blocks to fit between the 4 center sills.

Out of the jig with all nailing finished. Coupler blocks glued to the bottoms of the end platform sills.

Couplers attached. These are the "E" series 609 couplers from Kadee

The body bolster drilled and the 8-32 threaded inserts screwed in.

This picture was taken on the tightest curve on my layout. It's approximately 9-1/2 foot in diameter. I mounted the couplers back about 1/4" hoping for a closer coupling of the cars. The 609 coupler shank and knuckle extend approximately 1/4" out from the gear box when pulled. At rest, the shank and knuckle pull back in. This picture is of two frames just sitting on the curve. About 1/2" between the closest points of the end beams.

Pushing the cars apart with my fingers to get the maximum extension is approximately 1". Best guess on this test, the car might take a curve of 8' diameter but I don't have any curved track that tight to test them on.

Next up for me is to work on the CAD drawings for the sides and ends. For those of you that purchased the MOW caboose, you know I designed that car with double thickness sides and ends. The inner walls had interlocking tabs at the ends for strength. I plan on using the same methodology for these cars.    More next time.     Phil