Probably, the Franklin continuous rotary, but the improved Type B, and with modern metallurgy, it should be successful and reliable.
If my favorite steamer is the N&W J, why would i like to see a T-2 or T-1a? We have a number of very fine restored and operational 4-8-4’s. But the T-1 was unique, quite beautiful in its own way, and certainly would be a popular fan-trip locomotive. It does need a nice string of matched Tuscan red cars to haul with Mountain View bringing up the rear. And its first revenue passenger run should include Horseshoe curve!
No reason not to build a new T-1. The plans and drawings exist, the skills to do it exist, and who knows, there may be some “angel” out there who’s a rabid Pennsy fan and has deep, deep pockets who can make it all happen.
The only problem I can see is where to run it, but that’s no reason not to try.
And then we can get busy with a Niagara, a Hudson, an Erie K-1, a Hiawatha, “The Blue Comet”…
Another famous problem with the T1 was it was prone to slipping when at speed. With no warning at all, when there was a weight transfer, the front engine would lose its footing. Engineman were constantly dealing with this problem, sometimes having to stop the train to regain control. According to an article in a recent Keystone magazine, the problem was not so much the fault of the T1 as it was with the engineman. If he was sensitive to the T1’s behavior, slipping was a minor problem, if one at all.
I’ve been told that when a T1 was shopped at Crestline, they would go out clean and shiny. <<
High speed slipping did not have to be contained to front engine since its cause could apply to both engines alike .
Engineman were constantly dealing with this problem, sometimes having to stop the train to regain control. <<
This belongs to the heritage of great campfire legends of railroading ! Only to stop a slipping of four or eight powered wheels you’d be a fool to completely stop all the wheels of a whole train from turning at all . This would be like cleaning your living room carpet by flamethrower , no , more than that ! I may be prepard to believe some things about PRR drivers handling T1 engines – but not this stuff !
I’ve been told that when a T1 was shopped at Crestline, they would go out clean and shiny. <<
Well , that must have been at night exclusively and elusively - or there would have been some photos showing something better than the known inevitable dirt garb 1948 ff. More likely , they did as everyone did during steam’s late hours of fading out : minimum repair with minimum of cleaning just around parts to be worked on and disregard the rest .
Last year there was a great article in “Classic Trains” where the author exploded the “old husbands tales” concerning the T-1. I won’t belabor any of the details but the author said it best, the K-4 was “as simple as a hammer and as reliable as an anvil” so when the T-1 came along it wasn’t a surprise Pennsy veterans had some problems with it. Once they learned how to run and service it, no problems.
But as was said before, since the PRR had decided to dieselize passenger operations anyway the poor T-1’s never really had a chance. If the T-1’s had come out a decade earlier it probably would have been a different story. It’s also been said the PRR stuck with the K-4 longer than they should have, but that’s another story.
Hi Juniatha! The story as I read it a while back, and I forget just where, is the after the PRR’s mainline electrifications from New York to Washington and out to Harrisburg the Pennsy went a bit “ga-ga” for electrification and put steam development on the back burner, expecting to run wire clear out to Pittsburg. The thing was, that massive electrification project was made possible by a Depression era government loan. However, after that project there was no more money coming from Uncle Sam so the electrification stopped and they had to make do with steam. So, the K-4 was it, at least until they had to come up with something else. The “something else” was the T-1.
To amplify this a bit: while there may have been a nominally greater tendency or ‘propensity’ for the forward engine to break into high-speed slipping first, either engine could be the one that actually broke loose in a particular ‘event’. This is not the same problem as the low-speed slipping that was affected by weight transfer and the original equalization layout, etc and was predominantly observed on the forward engine.
On the T1s as built, there was no good way to determine which engine was slipping, and no separate throttle or ‘trim’ that could be used to correct only the wayward engine. A technically easy method for determining the presence of slip would be to use the ‘sensor’ portion of the analog system applied to the Q2s, which would indicate presence of slip “by engine” in the cab. Recording the relative incidence of these events would have given a better sense of the actual high-speed-slip dynamics. Might have been interesting to see how this would have developed if the T1s had remained in first-line passenger service…
Well said. I can provide at least one account of the actual procedure used for high-speed slip recovery;
I’ve been reading this thread with some curiosity. Not knowing in detail about steam. I have a question or two (maybe) . If T-1’s had a problem with slipping at speed did any other articulated locomotive have any similar problems and if not why not? The locomotive that comes to mind is UP3985 (in the modern era) or going back a little or maybe in the future UP’s Big Boy 4-8-8-4(I forgot the locomotive number). Thx IGN
This thread goes on and on debating whether the slippage problem was due to the design of the T-1 or the skill level of its enginemen. To my mind the very fact that we’re hammering away at this topic should be a warning against continuing on with this project. We’d literally be gambling with a huge amount of money here. How about we concentrate on getting that poor old K-4 that’s languishing at the Railroaders’ Museum in Altoona running. How about inspecting the M-1 at the Pennsylvania RR Museum at Strasburg to see what possibilities lie in that direction. In short, how about a little more practical thinking. A T-1 in good working order thundering down a Midwestern mainline was an awesome sight and sound spectacle but how much money do you want to gamble on recreating it?
you totally disregard one important factor : steam locomotive design is not done by gambling but by engineering . Engineering again is applied science really , not applied poker .
So , in order to build a new T1 - be it a replica , be it a T1b or even a T2 - is not a matter of applied guestimate but applied engineering , by itself vastly advanced since the days of this historical type of locomotive , again of which much more is known now than was back then before knowing what would be their actual behavior in service . At the time of their introduction the Duplex type held some specific imponderabilities and poppet valve gear was an advanced ambitious proposition . Engineering challenge of both features has since eased significantly .
If we build a new T1 we have two advantages : we can straighten out known compromises in design and we know what to expect .
Further , on the Pennsy the T1 engines had to do hard work 24/7 from the day they had left constructors yard . A replica or a new T1 / T2 will be destined for special travels with a totally different profile of monthly work in ton-miles and attendance applicable to the locomotive .
any type of steam locomotive - if not designed with hoplessly underdimensioned cylinders - could run into a slip at start , at low speed hill climbing ( constant high t.e. working ) or at speed due to instant transient loss of adhesion . Varying rail adhesion conditions are an issue in today’s modern electric traction - or why should they invest that much thought in better levelling out mass per axle distribution under all conditions of running and ever-improved electronic slip control .
In the Duplex type certain specific aspects of behavior also experienced in SE Mallet types proved to be more pointed and will have to be addressed by design of a new Duplex . What and why this is so I wiill not go into details here or this would become a tolerably long post to read . High speed slip was also experienced with German and French Pacifics and seems to have been known on the NYC, or else why should the Central have arranged those known high speed slippage tests with J-3a class locomotive to investigate what may happen under extreme conditions ?
Narig01 asked a questions about slipping problems with articulateds, and even mentioned UP’s 3985 by name. Well guess what, back around 1989 or so Steve Lee of the UP steam program addressed that very question in an article he wrote for “Trains” about running freights with 3985.
The answer was yes, articulateds would slip if not handled correctly. Big Steve said the secret to avoid same was to take it easy on the starts, a long slow pull on the throttle and not “pullin’ it like you MEAN it!” An attempted jack-rabbit start would cause the boiler water to surge toward the firebox end reducing weight on the front engine resulting in slips. Nice and easy on the throttle was the way to go.
Overmod refers to an “air assisted swing throttle.” I have never heard of this and would appreciate an explanation.
Also, regarding poppet valves, I think a helicopter flight control hydraulic system could be applied to a locomotive with good results. The Sikorsky S-76 uses two very compact and lightweight 3000 psi hydraulic pumps to power the flight control actuators, which adjust the flight path of the rotor blades as they spin. Such a pump could be driven by a small steam turbine. The actuators would directly move the valves with the valve events controlled by the engineer via computer or directly by mechanical linkage.Such a system would be very reliable, nearly maintenance free and robust enough to stand up to railroad operating conditions. What do you think?
The air throttle assist is shown in PRR drawing A436493. This system should provide the same proportional control and positive location that a Franklin Precision reverse does. A competing system from the late '40s was the ThrottleMaster.
There are many forms of servo actuation that can be applied to steam-locomotive valves. For example, air-over-hydraulic servos have a comparatively good history in fast proportional modulation of large valves (and it might be somewhat easier to make arrangements for power air on a locomotive than the very large volume of hydraulic fluid that has to be moved to cycle valves of adequate flow the number of times per minute required for a locomotive at high speed).
Historically, precise hydraulic systems of the kind you describe may have trouble standing up well long-term in typical locomotive operating environments (see the experience, for example, with Meier-Mattern valve gear). I consider the situation to be somewhat less critical on a locomotive with ‘typical’ non-desmodromic poppet or drop valves (the T1 being an example) tnan on one with piston valves (where position of the valve body may need to be reproduceably assured within 1/32" or better with the valve moving at considerable speed at the moment of admission, with what may be a long overall travel…) But there are still sensor and actuator concerns that I think are substantial.
A greater problem imho is that the effect on the locomotive of valve misposition at high speed can be catastrophic, as there are much greater forces involved than, say, in automotive-size IC engines with ‘electronic camshaft’ valve actuators. There are different syndromes when different parts of a full-servo valve system go out… few of them particularly pretty. Then there is the matter of road failures that incapacitate the locomotive – and there are a number of subsystems involved in the full-servo drive you describe which can produce that effect i
Hiawatha A 4-4-2 or F 4-6-4? The former would really be a one-of-a-kind rarety, good for short trains on mostly flat routes. Come to think of it, other than the CP Royal Hudson and one earlier CP example, both very fine locomotives, looks and performance, how many other 4-6-4’s are preserved, and how man operational? I think there are two 4-4-2’s at the Pennsylvania State RR Museum at Strassburg. Any Atlantics operational?
Hi Dave! No, there’s no operational 4-4-2’s that I’m aware of. One of the 4-4-2’s you mentioned at the Pennsylvania State RR Museum was used by the Strasburg Railroad until ( I think) the mid-1990’s. Ultrasonic examination revealed severe firebox erosion so the locomotive was returned to the museum. As the Strasburg was leasing it and didn’t own it outright they elected not to repair it. I saw it several years ago and it’s in beautiful shape, they didn’t return it as a junker, and the impression I got from the museum stafffer I spoke to was there were no hard feelings between the museum and the Strasburg, they realized the Strasburg was under no obligation to repair the firebox. Maybe it’ll be restored to operating condition at some point in the future? Anyone’s guess.
As an aside, that same ultrasonic unit revealed firebox erosion on so many other Strasburg engines causing them to be immediately pulled from service the Strasburg crew called it “The Death Ray”!
I recall that event. They also had a beautiful PRR D-16 that had to be taking from service and is also on display at the museum. Possibly long in the future, both locos can be restored to operation, but I would not hold my breath.
I Dave! I saw the D-16 at the museum as well, and it was in beautiful shape as well. And I’m with you, I’m not holding my breath waiting for any immediate repair and return to service of either locomotive. Maybe someday, but not soon.
Granted, you can’t tell a book by it’s cover, but to my untrained eye aside from firebox rebuilding it didn’t look like it would take much to put either locomotive in service again.