6024 King Edward 1

Deleted

 

This post suggests that is not correct: https://national-preservation.com/threads/6023.32903/page-56#post-2066559

Original cylinders are 16", and can ultimately be bored out up to 16.5".

New design cylinders are 15.75" and can ultimately be bored out to 16".

(See point 2).

It's all a bit moot anyway given the wheel diameter has also been adjusted, and all parameters change over the service life of the loco anyway.

Tom

 

Thanks Tom.

My original post as Tom has referenced is copied below. Regarding haulage capacity the maximum tractive effort is almost the same as the original design due to the smaller wheel diameter offsetting the smaller cylinder diameter. What will change will be the effective top speed but with current speed restrictions for steam on the main line this will be of no consequence.

Andy.

6024's new cylinders, how it was done - [edit] by the person who did it.

The need to reduce the overall width of the locomotive was well understood to avoid gauging restrictions, a number of options were explored.

1. Move the centre line of each cylinder closer to the frames on each side. Initially this was considered as a logical step but quickly dismissed because of multiple complications such as altering the valve gear, realignment of the slide bars and connecting rod etc. The greatest difficulty came from the positioning of the trailing bogie wheels which occupied the space between the frames and the cylinder casting, moving the cylinder inboard would have resulted in the tyres hitting the cylinder when the locomotive rounded a sharp curve.
2. Reduce the cylinder diameter. The original design produced a cylinder 16" in diameter with a bell mouth of 16 1/2" diameter, the bell mouth being where the cylinder cover locates into the bore and it defines the maximum diameter that a worn cylinder can be increased to before a liner is fitted. The expected work of the locomotive indicated that its life would be limited by factors other than cylinder wear so the front bell mouth was reduced to 16" and the bore reduced 15 3/4". The back bell mouth was reduced to 15 3/4" to that the cylinder at this end was stronger to withstand the stresses generated by supporting the slide bars. The reduction in bore would reduce the nominal maximum effort but this is countered by the reduction in maximum wheel diameter to reduce the locomotives height. The inside cylinders were fitted with liners to bring them down to the same diameter.
3. Reduce the cylinder wall thickness where the cylinder covers attach, this being the flange that is the widest part. The flanges at each end of the cylinder are massively strong but locally weakened by the holes for the 13 cover studs of 7/8" diameter each. Not only does each stud weaken the cylinder but it also introduces considerable localised stress. Replacement of the 13 studs of 7/8" diameter by 28 studs of 5/8" diameter not only allowed a reduction in wall thickness but it also allowed for a further reduction due to reduced localised stress. The original design has one stud on the horizontal centre line, the new design had two studs equidistant above and below the centre line and this permitted an additional small flat surface to make the flange narrower. In addition originally one of the cladding mounting screw holes coincided with the stud on the horizontal centre line, the consequential stresses around this hole could be discounted if the hole was moved to a location where the material could be thicker. Each of these changes allowed for a small reduction in width but overall they became significant.
4. Material. The original cylinders were cast from 14 Ton grey cast iron but the new cylinders are from 17 Ton grey cast iron, because of this wall thickness could be further reduced. SG iron was considered but as SG iron has poor wearing qualities a grey cast iron liner would be needed and this cancelled out any benefit of reduced cylinder thickness by the use of SG iron for the cylinder.

These changes reduced the width of the casting by 1 5/16" each side, in addition the cladding is recessed and bolts removed from critical locations to give a further saving of 1/4" each side. The overall width of the locomotive at cylinders is reduced by over 3".

The design and drawings were produced for 6024 Pres Soc and a Stress Engineer appointed to confirm to the satisfaction of the VAB the design was stronger than the original.

Andy.

 

If the new outside cylinders had been designed with a new bore of 15 inch and bellmouth of 15.5 it would have reduced max tractive effort ca 7%with original 6 feet 6 wheels.
If 6 feet 2 is dia upto date it is countered almost fully.
Running fast it would have had no influence on power as the limit is mainly the valve port areas.
Was it ever considered to enlarge the inside cylinders sligthly?

 

Best not to take 6024 too close to the Border! A loco named after the Hammer of the Scots may not go down too well in those parts of the world.

 

Does that forsee a battle between the King (6024) and the Edinburgh Warrior (60007 / 4498); the Battle of Upperby perchance ?