New Build Night Owl - 4709 Begins

Sure Hermod will help you out with that...

 

Only if the proposal involved three cylinders, each of different size, arranged asymmetrically about the centre line ...

Tom

 

If just changing from simple to compound, why change from the de Glehn position of the outside cylinders?

 

Yes, I noticed that the outside cylinders were too far forward to allow equal lengths for the connecting rods. It's the author's drawing though!

 

Pleased too but GWR is really to easy.
Loading gauge allow a single Saint size high pressure cylinder mid boggie placed.
Put a much bigger low pressure cylinder between frames driving unto first shaft a la Castles
Put a counterbalance conrod on the cylinder- free side.
Mid boggie placing of outside high pressure cylinder driving on second driven shaft allow long conrod and that is good for track.
While we are at it put Manor size wheels on and we can outdo a King on a good day.

 

Hermod's Roughrider!

 

Not really as fore and aft balance and even pull will be miles better than GWR fourcylindered before Bridge Stress commity 1927
But the real winner will be the County things.
5 feet 8 drivers alow 250 lbs boiler and 12 % more power.
Win-win according to undisclosable sources.

 

Hermod, how does a conrod without a cylinder work? Also, there's no balancing cylinder thrust on that side, hence it's very likely to be a very rough rider! I once had mainline footplate rides on 6998 (2-cylinder Modified Hall) and 5051 (4-cylinder Castle). On the former, everything was a blur on the backhead whereas the latter ran like a sewing machine.

 

You must be thinking of Mr Webb's 2-2-2 "Triplex" of 1895 - 9¼" high pressure cylinder on the right side, 13" intermediate pressure cylinder on the left side, 19½" low pressure cylinder in the centre. On a good day, Triplex was able to haul Mr Webb's personal saloon.

But this was not a GWR design, so no chance that it will be a GWS-related new build project.

 

Bal 1500 by Hermod posted Jun 12, 2021 at 2:18 PM

This was the problem that was not solved by Cox and his merry men.Two cylindered machies with 90 degree between cranks are very rough fore and aft.
Ad some balance in wheels and it becomes les violent fore and aft but becomes cruel to track.
A very great part of this bad behavior can be alleviated by the bob thing hanging in a swing link(not shown).
The pre 1927 GWR fourcylinders cheated the civils by letting front axle and second axle be compensated separately.
The two shafts loaded and unloaded up to 15 tons each but in antiphase.This removes much of horizontal axle bearings load
Stannier had got the message and to have 22 tons accepted by civils the two shaft were loaded against and fleeing each other up to7 times a second with 20 ton or there about.
The Cox brittania,the B1 ones and surely many others had drawbar problems because trains were run faster and civils had learned what the lousy CMEs had done pre 1927.
The nasty thing with mass forces is that they grow squarely with rps.
In my scheme the low pressure cylinder can only be inside frame due to size so there is a free bearing for big end of balconrod.
The sligthly higher cost of crank is countered by 10-15% more power/less coal and much steadier ride than two cylindered simples.
Compared to a fourcylinder power can be up 20% higher for same coal.
If in doubt feel free to ask.
I love to explain.

 

No, his is a design with one LHS HP cylinder, one LP cylinder between the frames and no cylinder on the RHS! See above.

 

Surely this is a 'non starter' ( starting a loco with only two HP cylinders is sometimes awkward, but with only one ? )

 

I thought the "Midland Compounds" had one HP (inside) and two LP (outside) cylinders?

 

I think they had a valve that allowed the low pressure cylinders to be fed with live (high pressure) steam for starting.

Tom

 

Similarly, many thousands of two-cylinder compound locos were used around the world, all with arrangements to allow HP steam to be fed to the LP cylinder on starting.

As an aside, many road traction engines seem to have a pair of cylinders of unequal size. Presumably two-cylinder compounds?

 

if interested try to seek forgotten books compound locomotives page 194
The Wienna Stadtbahn had a family of two cylinder compounds that made 3000000 starts per year.Goelsdorf designed

 

Compound traction engines and rollers are very common. Most commonly they are double crank but there are single crank compounds out there too. Most (if not all?) are fitted with a sampling valve (or magic button!) which effectively turns the cylinders into a double high arrangement. This is useful when starting or if ascending a very steep hill and maximum power is needed for a short period.

 

Looks like auto correct got you there ….. it’s a “simpling” valve.

 

Yes, quite right. It took me a while to stop it writing singling!

 

May God bless all who sail in you.