The main effect of the raised and angled center cylinder was a syncopated exhaust (Chuff ---- chuff — chuff – Chuff ---- chuff…) instead of the evenly-timed exhaust blasts of a two cylinder loco.
Another interesting effect, seen on Alco-built JNR C52 class Pacifics, was ‘out of position’ counterweights on the main drivers. They had to balance the inside crank and rod end as well as the usual outside rod, so the counterweight was not opposite the visible crankpin.
Union Pacific had some Gresley conjugating mechanisms with plain bearings, and some later ones with needle bearings. When wear problems showed up (plain bearings much more so) some of the plain bearing mechanisms were fitted with needle bearings. Most had the conjugating mechanism replaced with a third Walschaerts valve gear.
That syncopation is only the result of age, or incorrect valve setting. As built by anyone competent, the crank angles and valve actuation were arranged to give equal inlet and exhaust, and while the exhaust was triple it was regular.
(On Smith compounds and the like, as I mentioned, there was audible syncopation due to one out of every three exhaust events being internal, but that’s not what you’re talking about.) EDIT - I ‘mentioned’ this wrong. The exhausts on Baldwin 60000 were timed 90 degrees apart, so the audible ‘beat’ of the exhaust was as normal for a 2-cylinder DA engine…
Some of the audio recordings of three-cylinder engines, particularly a couple of the Nines near the end of their time, are almost terrifyingly mistimed. Here is a famous example.
The Australian locomotive with rack and pinion valve gear was the D58. This class started off as an order for 25 further D57 class for wartime traffic in 1942. The cast steel beds arrived from GSI but it was decided that the new locomotive should meet tighter clearances requiring smaller cylinders. The whole design went downhill from there. The rack and pinion gear was intended to allow longer valve travel, since Gresley gear had caused problems with overtravel in the centre valve, and the new gear was intended to eliminate this. When the first locomotive was steamed for the first time expansion locked the gear solid, and the gear was removed from the frame and cantilevered off the cylinder casting. Only 13 of the 25 D58 class were ever assembled starting in 1949 and their place was taken by Beyer Garratts.
Gresley called Holcroft to his office in London to describe the conjugated gear. The meeting is described in Holcroft’s autobiography. The layout used was favoured by Gresley, although Holcroft outlined the theoretical disadvantages at that initial meeting but Gresley felt that ease of access for maintenance outweighed the problems. Gresley wanted Holcroft to work for him on the G
I thought this was much later than Holcroft’s invention of conjugated gear for four-cylinder engines, and concerned something particularly germane to the present thread: how to make the 2:1 lever three-cylinder gear work correctly with an inclined center cylinder.
Holcroft’s gear worked entirely behind the cylinder block so all the valves and valve rods expanded in the expected direction. However if I recall correctly when there was not sufficient space behind the cylinder block, it would all be installed in front of the cylinder block, leading to some interesting rod arrangements to drive it.
I have always thought that part of the differential-expansion issue on Gresley-gear-equipped engines is that actual superheat under some running conditions, particularly WOT at high road speed, was much higher than expected, a likely effect being greater expansion of the valve relative to the port areas in the cylinder block.
Peripherally, but on topic: Can someone post (or re-post) drawings and details of the original ‘defective’ big-end arrangement on the A4s, and how the design was practically improved after Mallard’s ‘experiences’? I have read about this (I think in the ‘three designers’ book) but there were no illustrations of the specific design details.
M636C
Gresley called Holcroft to his office in London to describe the conjugated gear.
I thought this was much later than Holcroft’s invention of conjugated gear for four-cylinder engines, and concerned something particularly germane to the present thread: how to make the 2:1 lever three-cylinder gear work correctly with an inclined center cylinder.
Holcroft’s gear worked entirely behind the cylinder block so all the valves and valve rods expanded in the expected direction. However if I recall correctly when there was not sufficient space behind the cylinder block, it would all be installed in front of the cylinder block, leading to some interesting rod arrangements to drive it.
There has never been any conjugated gear for four cylinder locomotives: all that is required is a 1:1 rocking lever to drive the adjacent valve. This was widely used by the GWR, for whom Holcroft worked during the early years of the 20th Century. Holcroft was at least partly responsible for the detail design of Churchward’s standard locomotives, which drew heavily on contemporary designs from the ALCO Brooks works. The GWR four cylinder locomotives followed Du Bosquet De Glehn compounds but remained simple expansion (and used inside valve gear rather than outside). While with the GWR, Holcroft designed his original conjugated gear which used two 2:1 rocking arms and a central oscillating beam with the drive to the centre valve in the centre of the oscillating beam. This was inte
THREE CYLINDER locomotives in America were occasionally built before 1910 which heralded modern construction of 4 locomotives for the Philadelphia and Reading Railroad. These engines were 4-4-2 “Atlantic Type” locomotives and included one 4-6-0 “Ten Wheeler Type.” These Reading Railroad engines were superheated and used Walschaerts outside valve gear while the inside cylinder used inside Joy valve gear.
THREE CYLINDER steam locomotive development in the United States was not such a unique event in railroad history as one might assume. THREE CYLINDER POWER design as we know it really deals with the product development of ALCO Locomotive Works and its competiton with LIMA and BALDWIN Locomotive Works in the years from 1922 to 1930.
In the 1920’s when LIMA Locomotive Works was under the influence of William Woodward with his much heralded SUPER POWER concept. ALCO developed and was going strong with its own heralded THREE CYLINDER POWER concept as the way of the future.
At ALCO this began in 1922 with the development of the MOHAWK 4-8-2 rebuilds of New York Central NYC 2568 and NYC 2569. Going from a 2 cylinder to a three cylinder design in the rebuilding increased the hauled tonage and tractive effort capacity on these locomotives by 25%.
Following this in 1924 Lehigh Valley Railroad contracted an order for 6 engines, the first “New Built” of the ALCO THREE CYLINDER POWER with their 5000 series 4-8-2 “Mountain Type” designs.
ALCO Locomotive Works continued the new concept in developing the THREE CYLINDER 4-6-2 “Pacific Type” and 2-8-2 “Mikado Types.” Increase of tractive effort without total increase of axle loading was featured as well as the use of “Gresley” valve gear for the inside cylinder motion. Purchasers were Missouri Pacific RR, Louisville and Nashville RR, Delaware, Lackawanna and Western RR, Wabash RR, and the New Haven RR. Mexico wit
THREE CYLINDER locomotives in America were occasionally built before 1910 which heralded modern construction of 4 locomotives for the Philadelphia and Reading Railroad. These engines were 4-4-2 “Atlantic Type” locomotives and included one 4-6-0 “Ten Wheeler Type.” These Reading Railroad engines were superheated and used Walschaerts outside valve gear while the inside cylinder used inside Joy valve gear.
THREE CYLINDER steam locomotive development in the United States was not such a unique event in railroad history as one might assume. THREE CYLINDER POWER design as we know it really deals with the product development of ALCO Locomotive Works and its competiton with LIMA and BALDWIN Locomotive Works in the years from 1922 to 1930.
In the 1920’s when LIMA Locomotive Works was under the influence of William Woodward with his much heralded SUPER POWER concept. ALCO developed and was going strong with its own heralded THREE CYLINDER POWER concept as the way of the future.
Denver and Rio Grande Western in the market for Rocky Mountain pulling passenger power settled upon the 4-8-2 “Mountain Type” three cylinder design. BALDWIN Locomotive Works produced this successful three cylinder D&RGW class 1600 series of 4-8-2’s.
This 4-10-2 demonstrator locomotive as it was envisioned by Baldwin was an extremely high technology engine that was never duplicated. The Baldwin 60000 demonstrator engine remains today brand new yet never sold at the Franklin Institute in Philadelphia, PA where Baldwin got rid of it through donation in what appears as a tax write-off.
Shop men from Baldwin actually changed out the bearings on the 60,000 at the museum years ago. As you stated, the limited movement made the original bearings egg-shaped. I don’t know if they have been changed again, but I do know that they have been changed out at least once due to the wear and tear of “museum service”.
I’m surprised nothing has been said about the seven 3-cylinder 4-6-2s rostered by the Mexican Railway (FCM) which lasted in service until the early 1960s. They were wonderful to see and to listen to in regular passenger service. Before the FCM was absorbed by the NdeM these engines were well maintained and proudly cared for by their engine crews. They were assigned to daily passenger trains between Mexico City and Esperanza, with tight schedules requiring speeds of up to 100kph. I was privileged to two cab rides in 1960 on these beauties. The first four, numbers 130 through 133 were built as simple three cylinder engines with Gresley gear by Alco-Schenectady in 1928. Three more, 134 thriough 136 were built in 1938 by Montreal Locomotive Works to the same specs. Unfortunately, NdeM, while still heavy in steam in the early 1960s, they shoved the FCM Pacifics off to local freight service to run out their service life before scrapping them.
See what happens when you rely on memory. I haven’t been to Philadelphia in more than twenty years…
I’d never seen that drawing, of course… I’ve got copies of the photo of 60000 but never checked them closely. Enlarging that at the link to 100% is quite helpful.
60000 has three valve gears, but two of them are driven from the same eccentic crank.
Does that mean that the HP cylinder was 180 degrees ahead of the right hand LP cylinder, and the left cylinder 90 degrees behind that?
60000 has no conjugating gear, since the centre cylinder’s valve has no connection to the left valve gear, only the right valve gear…
The link and crank visible on the right side of the locomotive look very similar to the drive for the Henschel conjugating gear, so the drawing is very important in showing what is actually there… The rocking shaft is a bit too far forward for the Henschel conjugating gear to fit there anyway…
I would expect that a Smith compound setup like the one on 60000 would need separate HP cutoff, if for no other reason than the fixed expansion ratio will not be ideal. This would be best addressed by trimming cutoff and throttle opening on the HP vs. cutoff on the LP to best use the available ‘exhaust’. I would suspect that a four-cylinder de Glehn-du Bousquet would have its HP and LP cutoff manipulated in analogous fashion.
I do not know how the control was arranged on 60000; perhaps Mike (wanswheel) can find something definitive. My naive idea would be to have a ‘trim’ control on the center cylinder that would allow it to be adjusted separately from the LP cylinders, but then have all the gears worked running by the same power reverse. Fortunately the engine still exists and someone doing research could at least in theory gain full access to the cab and running gear, and watch the result of adjusting the controls that are there, with HR video running to observe the valve spindle motion outside and inside, to see how the trick is done.
Several French compound 3- and 4-cylinder designs also drove the lead driving axle, including a class of PLM 4-8-2’s built in the 1920’s and early 1930’s.
M636C
Does that mean that the [BLW 60000’s] HP cylinder was 180 degrees ahead of the right hand LP cylinder, and the left cylinder 90 degrees behind that?
The outside cylinders were 90 deg to each other-- the center cyl was 135 deg, plus or minus its inclination.
That is what I would have expected, since that is the standard arrangement for Smith Compounds, including the 240 Midland and LMS locomotives. What I can’t work out is how the single RH eccentric provided drive to a valve for a cylinder 135 degrees from that which it also provided the valve motion…
Is there something not seen in the drawing you kindly provided?