• Norris Valve Gear

  • Discussion of steam locomotives from all manufacturers and railroads
Discussion of steam locomotives from all manufacturers and railroads

Moderators: slide rules, Typewriters

  by ArdsleyTank
Hi, this is my first post here, so I hope I'm in the right place.

I have looked everywhere, but I simply can't find any info on the subject. What type of valve gear did the Norris 4-2-0's (B&O Lafayette) use?

I have checked photos, and can't find any details.

Thanks for any help,
  by Allen Hazen
Welcome aboard!
I think this is definitely the right place, but getting an answer may take a while: check back periodically. … The Norris locomotives were very early: before the invention of most familiar valve gears. My guess is: something complicated and inelegant, but I'll look at my (small) reference library to see if I can find anything closer to a real answer.
  by Allen Hazen
I've got some good news and some bad news.
Good news is that I have a copy of "Loco Profile #11: The Norris Locomotives." (This is a 24-page pamphlet, published in I think 1971, by a British company that also published Aircraft,Car, AFV and Warship profiles. There were at least 24 issues in the locomotive profile series, which were later collected into volumes. I have a small number of the pamphlets.)

Bad news is that the paragraphs on valve gear, which I'll quote below, do more to illustrate the difficulty of giving a verbal description of such machinery than they do to clarify what, exactly, it was! (I know of a couple of other possible sources of information, so check back in a while-- but I won't try to follow them up for at least a few days.)

First paragraph, describing the 4-2-0 locomotives from the 1830s and early 1840s"
"Steam chests were higher than the cylinders and closer to the engine centre line, and valve spindles were actuated by short cross rods. Simple hook, and from 1842 V-hook, four eccentric gab motion was fitted to practically all Norris locomotives until the mid-1850s; but many in the 1850s had Septimus Norris's patent separate expansion valve back of the main valve to give a 50 per cent cut-off. This was driven by an additional eccentric after crosshead drive had been attempted."

Comments: there is no sign of an eccentric crank on the outside of the driving wheel, so the eccentrics must have been axe-mounted. Going by a photo caption, at least one Norris was later rebuilt with Stephenson valve gear, which also typically used axle-mounted eccentrics.

Norris built locomotives with a number of different valve gear arrangements. There is a photo of a 6-2-0 "Crampton-type" built in 1849-1851 with "Stevens valve gear": but this was a special order and may have been as much a customer design as a Norris one.

Second paragraph, about later production"
"Production at the Philadelphia works in the 1850s was largely American-type 4-4-0, but for these and other types V-hook gab motion was retained until 1853-1854, and then was only gradually superseded by expansion-link gears; the last gab-fitted engine was as late as 1856. Engines fitted with Septimus Norris's back valve carried a plate: "Septimus Norris Variable Expansion Valves." …"

Question for anyone reading this who actually knows some engineering: locomotives of this era operated at what we would think of as very low boiler pressures: 100p.s.i. or less, sometimes much less. At a guess, the steam wasn't very hot: in which case allowing much expansion would have risked damaging condensation in the cylinders. Is it conceivable that railroads, both in the U.S. and Europe (since Norris had a healthy export business) would have been satisfied with something as simple as this suggests, a locomotive with basically "one speed forward and one speed back" as far as valve gear was concerned, control being totally a matter of throttle?
  by ArdsleyTank
Ah yes, that does make sense.

Gab valve gear was early enough, I was guessing it was that or Stephenson...

Thank you for the information. Any further info is appreciated!
  by Allen Hazen
Ardsley Tank--
Sorry to take so long in getting back to you. (It may be as long again before I try to see if another book in my collection has anything relevant, though.)
Angus Sinclair's <i>Development of the Locomotive Engine</i> (New York, Angus Sinclair Publishing Company(*), 1907; new edition with annotations and afterword by John H. White, Jr.(**), MIT Press 1970: Interlibrary Loan is your friend!) has a 50 page chapter on valve gears… which doesn't mention Norris. But I think it's relevant anyway.

(1) There's a paragraph (p. 446 of 1970 edition) that begins "It seems strange for a twentieth century engineer to reflect upon, but it is a fact that the pioneer engineers had very vague ideas about the advantage of steam expansion and how expansion could be most readily secured. This was curious for Watt had invented an indicator to show the practical action of expanding steam." And goes on to give some examples. It appears that locomotive designers in the period of the early Norris engines really were content with "one speed forward, one speed back" valve gears giving essentially constant cut-off. From our point of view this is maybe a good thing: it means that, in trying to imagine what a Norris 4-2-0 of the 1830s had, we can imagine the simplest and crudest arrangement imaginable in the confidence that it might in fact be right! (Grin!)

(2) There are some drawings of early valve gears: the clearest perhaps on p. 449, captioned "Common Form of V-Hook Motion." Start with two eccentrics on the axle. (Given the small forces on these early engines, they can be pretty narrow and, since they are side by side, can operate connecting rods that aren't in too different planes from each other.) One is for forward motion, one for backward. There are rods (I'll call them rods, anyway) running from the eccentrics to the lower pin of a rocker whose upper pin actuates the valve rod (= extension of valve stem). The rod for forward motion is angled up, so its hook end (= the end away from the eccentric) is above the pin on the rocker, the one for backward motion angles down, so its hook end is below that pin. The upper (forward motion) rod has, as its "hook," an inverted V shaped fork, and the lower a right-side-up V. The reversing gear involves a lifting lever that lifts the two eccentric-to-rocker rods simultaneously. To go forward, lower it and the upper, inverted, V slips over the pin on the rocker and rests on it. (The open end of the V means that it will catch the pin on the rocker even if not lowered very precisely over it. The apex of the V has a slot so, once engaged, the pin on the rocker has more or less vertical surfaces in front of it and behind it, so it won't tend to slide out as it would if in contact with the slanted legs of the V.) To go back, lift the rods so the forward-motion hook is freed and the V of the backward-motion hook engages. … Since one probably wants to go frontward more than backward, it makes sense for the foreword-motion rod to be the upper one: gravity will help keep it engaged. … … Crude and probably very inefficient, but the only valve-gear arrangement simple enough for me to understand it on a first look at the diagram!
(*) I think Sinclair ran what was basically a proprietary railroad correspondence school, and he published lots of educational matter. Including a drawing -- included as a fold-out inside the back cover of the 1970 edition of the book -- of a 4-8-2 locomotive with 385 parts numbered and identified.
(**) Was the curator of the Smithsonian's Museum of History and Technology. Wrote many things on the history of steam locomotives.
  by Allen Hazen
Bad news. I have one other book ("The Steam Locomotive in America" by Bruce) which I thought MIGHT contain some relevant information. Alas, it doesn't.
  by ArdsleyTank
Hey, that's no problem at all. In fact, you've already confirmed what I thought.

They had Gab valve gear, one of the first most rudimentary valve gears, or should I say reversing gear?

The L&MR Lion used it, along with most engines of the 1830-40's. So, thank you for your info!