Broadway Limited T-1 4-4-4-4 (or is it a 4-8-4 ? )

I got a chance to see one run last week at a friends layout. It pulled the very same train that a few weeks before could not be pulled by a Lionel Challenger, and did it beautifully! No wheel slip at all, and ran very smoothly. Great sound too! The chuff, and whistle made the Challenger sound like a sick goat! I'm not a Pennsy fan, but if I were, it would be a "must have" piece. Chooch

Froggy,
I never thought about the 4-4-4-4 as being a 4-8-4, but it is interesting. However, I believe it is a 4-4-4-4 as an articulated engine, should properly be a 4-4+4-4.
Bob Rule, Jr. Hatboro, Pa.

=>Well, is it a 4-4-4-4 or is it a 4-8-4
It's a 4-4-4-4. If it were articulated, it would be a 4-4+4-4. See?
At least, that's how it was before the simplifiers got hold of the Whyte's classification scheme.
Wolf Kirchmeir ................................. If you didn't want to go to Chicago, why did you get on this train? (Garrison Keillor)

A 4-cylinder 4-8-4 would have been really intersting. I always wondered why they built these as duplexes.
Other countries built more traditional 4-cylindered engines where the opposing piston thrusts balanced each other out, giving a very smooth riding engine with much lower hammer blow to the track than other designs. When they are designed this way you only need 2 sets of valve motion, because the same set drives two cylinders at the same time.

These are vey nice engines (the models). In DCC the sound can be turned off fairly easily, and there is a volume control anyway if you just want to turn it down. The detail on it is very nice. People compare these to brass engines and compared to them, yes, there are a few items probably not there like operating cab roof vent etc, but they also are alot cheaper. The paint is excellent. It comes with two of the four drivers blind. Flanged ones are included. Thus it handles curves fine. Gladhands? Yeah it can just be cut off. It pulls a TON. Runs slowly. The only issue I have is the front truck is lightly loaded (spring pushed down) and once it a while it picks a switch. My track work is not perfect so others may not see this. Overall a very , very nice model. Of course I got mine at a discount outfit so that factors in to my price/value equation. One other thing about BLI locos. They need clean track and the wheels on them cleaned once in awhile, but if you are DCC already then this is probably SOP.

Hmmmm..........we've heard that before around here, this business of 4-6+6-4 instead of just 4-6-6-4 to indicate an articulated locomotive. If I was a European and referred to a six-axle/six-motor diesel as a Co-Co, then I would certainly use the European 4-6+6-4 to indicate either a Garratt or an articulated locomotive. Being a North American and using that convention, however, I would say a six-axle/six-motor diesel is a C-C and an articulated Challenger is a 4-6-6-4. I cannot argue that you are wrong and I am right. In fact, the 4-6+6-4 convention does help to avoid confusion- to a point- between multi-engined rigid and articulated frame locomotives. It's just that it is not the convention of common use in this part of the woods. Add to that the fact that multi-engined rigid frame locos were basically confined to a couple of classes on the Pencilvania Railroad, and none of them had a wheel arrangement that corresponded to any articulated locos that ran on the continent.
Anyway, as regards the class T, it could be called a Duplex American, Double American Duplex Atlantic, or just a Duplex, Double Atlantic, 4-4-4-4, Duplex Northern, Split Northern, EE-1, AA-1 or any of several other names. The 4-6-0s were class G and the 4-C+C-4 electrics were class GG. It stands to reason that if the 4-4-0 was the class A then the 4-4-4-4 should have been called the AA-1 and not the T-1. The 4-4-2 was the class E so this could have perhaps been applied as well to the 4-4-4-4.
Anyway you look at the thing it is a beautiful machine I don't model the Pencilvania or even steam. I don't even model a railroad that exists in any part of the country where you would have ever seen one of those machines, but I still would like to have one. A silent one with no glad-hands.
.............F>

A Garratt would be a 4-6-4+4-6-4.
Ralph Johnson regarded them as divided drive 4-8-4s.

Actually no. There were several classes in the UK (and AFAIR mainland Europe too), in the late Victorian era.
These were "double singles" of the 2-2-2-0 and 2-2-2-2 wheel arrangements. The London and North Western Railway had some designed by Webb, and the London & South Western had some designed by Drummond.
The idea was to reduce friction in an era when engineering wasn't as precise as it was a few decades later, hoping for faster and more free-running locomotives.
These were 4-cylinder compounds which contributed to some of the problems. And rigid duplexes which made it worse - duplexes are inherently slippery engines as there is no weight transfer between the two halves. And single drivers are by their nature also slippery due to lack of adhesion.
Webb's engines used Joy valve gear which isn't a particularly good one in the first place, on the high-pressure cylinders/axle. But the worst feature was the use of live-steam-model type slip eccentrics on the low pressure cylinders/axle - which meant a fixed cutoff at the LP end.
Something funny and unheard of happened on more than one occasion....
Any live steam modeller will tell you that slip-eccentrics move into forward or reverse once the engine is moving. On models they raise steam and then give the engine a push in the direction the want it to go.
But in this case the engine would back onto a train at the terminus.
Leaving the slip eccentrics in reverse.
The idea was that steam applied to the HP end would get it started, and that would set the slip eccentrics to forward.
But there was only a small proportion of the weight on the HP axle. So it could slip very easily.
While the rear cylinders/axle were still in reverse.
So the HP axle would slip in forward - then steam would reach the low pressure cylinders which were still in reverse....
And you had the sight of the driving wheels spinning in opposite directions.
The first 2 pictures at examples. The inside cylinders drove the front driving axle, and the outside drove the rear. There is no side rod although you have to look hard to realise this.

On Sun, 18 Jan 2004 12:57:50 +1100, Mark Newton
wrote:
Right. I've very little experience with Garratts and need to have a watchful eye on the lookout when I bring them up.
Yes, and I tend to conform to that line of thinking as well. I have always thought of the thing as some sort of 4-8-4.
............F>

In North America
I was limiting my comments to North America when I said that. I don't know very much about European railways or locomotives, and so try to keep my comments on them to a minimum.

It could also be a 4-6-0+0-6-4.
Were any Mallet-type (US-type) articulateds built with inside trailing wheels?
This notation can get even more complicated. For instance some early Crampton-designed single drivers were described as (2-2-2)-2-0 with the brackets showing that it had three rigid carrying axles in front of a single driving axle, not a 6-wheeled truck.

Yes, it could*. My point was that a Garratt described in Whyte notation would be x-X-x + x-X-x, not x-X+X-x. I used the 4-6-4+4-6-4 notation merely as an example.
*In which case it would the unique Colombian Pacifico Railway engines built by Armstrong Whitworth.

The intent was to bring the piston thrusts and the weight of reciprocating and rotating parts below those of a comparable two-cylinder 4-8-4 engine with the same power output, to obtain higher running speeds. Also, the divided drive layout offered improved steam distribution and smaller cylinder volumes.
In respect of these criteria, the T-1s were a success.
The divided drive concept was well developed in Europe, in particular on locos designed by the French engineer Andre Chapelon.

Who's Ralph Johnson?

He was Baldwin's Chief Engineer during the late steam era, and a vocal advocate of duplex/divided drive steam locomotives. He was able to convince the Pennsy to buy the first two T-1s in 1940, otherwise Baldwin planned to build a demonstrator locomotive for themselves.

He got it from De Glehn, as did Churchward in England. But these engines weren't duplexes - they were fully coupled with the inside cylinder(s) working the first driving axle, and the outside cylinders working the second one.
With four cylinders, only two sets of valve motion were needed because the adjacent inside and outside ones effectively opposed each other. One pushed and the other pulled. The thrusts balanced each other out so there was very little hammer blow on the track and they were very smooth riding.

Good point Dan, perhaps Whyte is not really the best system for describing Garratts. But I doubt I'll convince many people here to start describing our local Garratts as (4-8-4)-(4-8-4)...
Cheers,
Mark.

Which is why I qualified my comment about them being successful. Personally, I'd hate maintain one.
Sadly, yes. But they were no less impressive for that.
Cheers,
Mark.

Yup! Confusing at best.
Just like most people HERE would describe them as 4-8-4-4-8-4, which could be interpreted as just about ANYTHING!
Reminds me of the late Jerry Drake's famous (in NMRA circles) tounge-in-cheek HO scale BSL 2-4-6-8! ... with every driver set a different diameter to boot! At least it wouldn't get 'synch locked' like some other duplex or articulated locos could. The goofy model actually ran pretty well. Does anyone know who ended up with this model after Jerry's estate was sold? I have several of Jerry's pieces, but I don't know what happened to that one.
Dan Mitchell ==========
Mark Newt>