Topic: 3' NG Shay design thoughts

[locodan]

Hi Chuck,
I was aware of the Ulin castings and I have one of his catalogs, it came with detail photos if the engine trucks and frames. I do not know if the castings are still available but they very nice bronze castings. The lower engine bracket is also a bronze casting.
Thanks for the reminder.

Bronze castings might be the way to go. I have cast parts up to about a half a pound with very good results. I will have to finally work out the puzzle of a steam chest core box. This might be a good use of 3D CAD as I have never really grasped the 2D drawings of the patterns for a steam cylinder.
Cheers Dan

[chucka]

Dan,

Don't know if you have seen this or not.  Go to the following website and click on the august 11th, 12th dates for the "Narrow Gauge Meet".

http://www.bittercreekwesternrr.org/events.html

There you will see pictures of a beautiful 2.5" scale model of West Side Lumber Company #15 narrow gauge shay.  The prototype is shop #2645.  3---11 x 12 cylinders.  Class "C"---60 tons.  The model was built using Ulin Locomotive Works castings.  So, here is an example of available commercial castings that may be interest?

Chuck

[locodan]

The approach I am using is to draw the entire locomotive using LLW drawings. The model will attempt to follow this plan. Obviously this will not be totally possible with a limited budget of time and money.

The frame of S/N 797 was a 9” 25# I beam. This can be approximated by 2” channel welded back to back. I can really see the advantage of 1/5 scale over my usual 1:13.7 scale as it is much simpler to find stock in nearly the correct size.

The gear used on this Shay was # 13.  The pitch diameter of the gear is 20.63” with 37 teeth and the PD of the pinion is 9.52” with 17 teeth. The circular pitch is 1.75 and the face length is 5”. Boston Gear makes a 2:1 gear with 40 and 20 teeth with pitch diameters of 4” and 2” and a face of .72”. This is just about as good as it gets in gear selection. The face will always be a bit short using modern commercial gears.

The truck bearing boxes will be built up construction using steel and arc or gas welding. The right truck box will be designed for either the Boston Gear or the scale gear for those who want to cut bevel gears. I have to draw the scale brasses to see how big they are and I am hoping they are not bigger than I can handle with lost wax casting.

The special part of this engine is the crankshaft wedge adjusters. They will be fully operational.

This will be the fifth Shay I have drawn from LLW prints hopefully this one will go past the drawing board.
Cheers Dan

[locodan]

Hi Ferd,
A gauge change between 7.5" and 7.25" is easy. I saw an article most likely in Live Steam some time back on this issue. As I remember it the left drivers were keyed on the axle and two snap rings were located so they would act as stops when the wheel was shifted. A 1/4 spacer was was moved from one side to the other. I do not remember the details of the removable spacer but small Allen cap screws could be used to join the two halves.

I have 10 acres for a track and enough grade make working brakes very necessary. I have also seen a photos with track in a running stream. I have a dry wash that is bed rock where I plan to cross. I only have to run in a rain storm.
Cheers Dan

[medic]

I would love to be hauled by a Shay. Our track is limited to 5mph as are most in the UK for public hauling. Even 3mph wouldn't hold up that much.
I agree 'mainline snobbery'
medic

[Ferd]

Yes, the issue is one of speed.  That is only a problem at our track on days when we haul , the public as passengers so we typically do not run Shays then. 

Sounds like mainline snobbery to me  dd dd dd ro

[russ]

Yes, the issue is one of speed.  That is only a problem at our track on days when we haul , the public as passengers so we typically do not run Shays then.  If I was building a Shay, I wouldn't regear for speed.  Watching a Shay at speed thrashing its little heart out is not a pretty site and probably results in undue wear and tear.  They were pruposely designed to run on horribly bad track and grades and were magnificent for that puprpose.  I recall seeing a picture of track simply being laid down on the creekbed while the creek was still running of course.

Russ in Oakville, Ontario, Canada

[locodan]

Hi Ferd,
A group project might be the thing to get me off the drafting board and in the shop making chips. I am working on this with another fellow who is on vacation now but a new Shay design is a big project and I for one would welcome the help.

My Live Steam magazine collection only goes back to 1977 but the only Shay construction series I have seen are the 2 by Kozo and the one by Bill Harris. If there was another let me know.

I assume the negative response to Shays trackside is the slow operating speed? There is not much we can do about that besides race the steam engine. It is my understanding that all or most rod engines ran about 300-350 RPM the size of the driver determined the speed of the loco. All Shays used a gear ratio between about 3:1 to 2:1. We can not change either the gear ratio much or the driver size much and stay with prototypical appearance. Not really much we can do about speed racers.

I for one find the sound of a Shay very relaxing. At work on the ships if the main engine was purring along all was well.
Cheers Dan

[Ferd]

Hi Dan
Count me in. That is my dream project 7.25/7.5" 1/5 Shay. Dual gauge so I can run at our local clubs (7.25) and 7.5 for when we travel as a family (wife and kids) visiting railroads across North America running the shay on every track we pass.  May be a great group project (where various tasks are divided amongst those that are taking part). I had planned on  using Kozo's latest book as a starting point and modifying the plans to fit an actual prototype. There were a series of Shay drawings run in Live Steam magazine in the past, I would have to go through my back issues ( have nearly every one since 66 ) thanks to eBay. Wonder if the gearing can be modified so that all the other club members stop groaning every time a Shay shows up at the track. Mainline locomotives find Shay's a cumbersome sewing machine like nuisance.  ROFL
cheers Ferd

[locodan]

Hi all,
Here are some thoughts on a 1/5 scale 3 foot NG Shay for 7.5” track. The choice of a prototype loco is any 2 or 3 truck Shay 60 tons or less. This is a lot of engine bore and stroke combinations. I think that the engine is the most important part of a Shay locomotive. It is certainly the most fun part to see run. This is why I would like to use a commercial set of cylinder castings. Shays often ran in the woods without cylinder lagging so a cast cylinder will add realism. The cylinder castings I am most familiar with is the Stuart Turner line. The #9 is a likely candidate with a 1.5” bore and stroke. This scales to a 7.5 bore and stroke which would work fine for 7x7 or 8x8 Shay cylinders. The #1 Stuart cylinder with a 2” bore and stroke will work exactly for a 10x10 Shay cylinders. All the engine sizes so far mentioned had both 2 and 3 cylinder versions. For a really powerful Shay model #5 cylinders with a 2.25” bore and a 2” stroke is a nice fit for 3-11x10 Shay cylinders.

The engine choice, in my opinion, has to be made first because the amount of heating surface in the boiler design can only be calculated after the engine and MAX rpm is chosen. I usually use 300 RPM for this figure but I have the actual LLW engine design RPM for any Shay engine in production in 1924.

The choice of 2 or 3 cylinders, and the choice of the old or new style of cylinders is a matter of what looks good to the builder. I like the old style cylinders that were a single casting that included the crosshead frame and the crankshaft bearing.

If anyone of other cylinders to fill in some of the gaps in sizes for this scale please share the info.

My latest order of Shay drawings from the California State RR Museum will hopefully have most of the special engine used for S/N 797. This was a Pino Grande #5 and it had a 3-9x8 engine. This was the old style of cylinders and what made this engine special was that it had wedge adjusters for all the crankshaft bearings. This was a very rare feature on old style cylinders and this is the smallest example I have found in the records. Now I only have to wait a few months until the CSRM order box fills up and they process another batch Shay drawing orders. 

Cheers Dan Rowe