There is a group that is recreating the PRR Class T1 4-4=4-4 duplex with the avowed intention of breaking the speed record for steam locomotives. OK, great. BUT....I can't imagine any Class I where such an attempt might be made letting it happen. No management will permit any private excursions - no matter what the speed - due to the disruptions to their operations, they don't have track and roadbed capable of supporting 125 MPH plus operation, the exposure to liability suits should something go bad terrifies them (and they won't accept an excursion operators' insurance to cover them) and view the idea of the terrible publicity if there is a wreck with horror. What about UP? Their steam program is a carefully controlled corporate effort under the total control of Omaha with equipment of known capability operated within its known limits. As Marcus Tullius Cicero put it, "Qui Bono?" How does UP benefit by hosting such an operation? So what's the deal? How do the T1 folks intend to get around this?
This was extensively discussed in the original feasibility plan and should still be identifiable on the Trust site.
Any high-speed testing will be done on the TTCI Fast Loop in Pueblo. There is design and planning in place for the instrumented wheelsets necessary for this. Instrumentation to detect emergent resonances and systems capable, if necessary, to break them well enough and long enough for safe deceleration, were also part of the design spec.
Before any high-speed testing is done 'IRL' the design will be fully multiphysics-analyzed, and the locomotive will be run at all presumptive speed and power ranges on its roller rig before any actual high-speed operation is made.
The world record still is held by the famous LNER A4 Pacific "Mallard", which pulled an actual train with that speed on a mainline.
Are there any cars that can run that fast around? If not, the speed record will be subject to challenging.
Happy times!
Ulrich (aka The Tin Man)
"You´re never too old for a happy childhood!"
THIS is the only rig I would even feel marginally safe in performing a speed test on an unproven (copied) design of a reciprocating steam locomotive:
Locomotive_Testing_Plant_(1904_World's_Fair) by Edmund, on Flickr
Unfortunately, this one — and the one at Altoona — are long gone.
Perhaps the British kept theirs?
Regards, Ed
Tinplate ToddlerAre there any cars that can run that fast around? If not, the speed record will be subject to challenging.
The short answer is spelled PRIIA; the slightly longer one includes Amfleet with some suspension modifications. There are other possibilities including some waiver activity (not unjustified in the highly controlled conditions at TTCI). The plan was to use AEM-7 style trucks, motors and control for the regulated-dynamic-load dynamometer car, which also gives inherent high-speed capability if correctly secondary-suspended. Which it would be. Since the AEM-7 stuff will likely be gone, or restricted from running by Amtrak policy, some other source of 125mph+ motored truck may be needed -- Siemens from ACS64 or Chargers would work fine.
Even short recourse to history will reveal that not only was the T1 exhaustively tested on the Altoona plant (making appropriate hay of that 'unproven design' crack) but was one of the locomotives that exceeded its measurement capacity. There have also been great technological improvements in high-horsepower static dyno equipment since the age of the St Louis fair or the construction of Rugby, and I recommend these to your attention.
I should probably add that much of the early rhetoric about 'smashing Mallard's record' or whatever was more than a little misguided and I believe has been 'walked back'. It is obvious in many ways that even a T1 with the 1948 improvements and full dynamic balancing with low overbalance is vastly more capable than an A4 Pacific; 5550 will be considerably more so. It proves nothing significant to go demonstrate that with blood and treasure.
As I've pointed out, there are three steam replica projects of far more relevance in the historic-record context, all of which are smaller scope than the T1 Trust's project. One of these is a replica 86" drive McQueen/Buchanan 4-4-0 (to prove the feasibility of the first true 100mph sustained running); the other two are, respectively, a full contemporary re-creation of PRR 7002 as she ran during the alleged 127+mph time (I personally doubt anyone will arrange that, but there's nothing shy of building one, learning to run it fast, and trying that could disprove that), and a replica Hiawatha A class, the only thing really likely to have been faster than a T1. (Don't come to me with fibs about alleged '120mph' 3460 class locomotives or those Milwaukee F7s so suspiciously similar in all respects to the C&NW E-4 that couldn't even get to 100mph with a train; on the other hand Mr. Bruce, who ran Alco and was in a peculiarly good position to know, said the A was easily good for over 128mph ... you'll appreciate where he got that number ... and we owe it to his memory to find out if he was right.
(BTW all these things are 1:1 scale model railroading so it is completely within TOS to keep discussing them here.)
OvermodEven short recourse to history will reveal that not only was the T1 exhaustively tested on the Altoona plant (making appropriate hay of that 'untested design' crack)
gmpullmanon an unproven (copied) design
What I was implying by the untested design crack is that although the Built By Baldwin T1 WAS thoroughly tested AND proven on the Pennsy's West end, a COPY made solely from blueprints alone has NOT been tested and is not a duplicate of the original locomotive but a fabrication of what may be available in today's marketplace as far as steam locomotive knowledge and parts resources that may be at hand.
Do you think the T1 trust has the same knowledge, skills and capability that the fully-staffed Baldwin Locomotive Works and the Altoona Works had during the development and building of the Pennsylvania Railroad's order of the T1s?
Will it have a cast steel bed plate? Will the steel have the same characteristics. From what I understand the boiler is being fabricated form one inch plate. Will that have any effect on the center of gravity from the original T1? Will it handle curves in exactly the same way as the Baldwin product?
T1_ES by Edmund, on Flickr
PRR Photo
Sorry if I caused you any grief in your short recourse in history.
Warm regards, Ed
Trust me, Ed, there are people with comparable intelligence and practical experience working on the detail design of the locomotive. And on recreating the materials science and manufacturing methods. And testing and modeling of the design with tools that BLW could only have dreamed of.
You can carry on with that whole 1940s-knew-best line if you want; this is America and I'm not the forum police. I would point out, a bit archly, that Baldwin certainly didn't build these engines in a way considered particularly successful, including the initial design and fabrication of their 'non-one-inch-plate' boiler wrappers; I think you might want to look into precisely what the engineering committee at the Trust is doing before you half-acidly go to town disparaging it as incompetent.
This with all respect to your considerable historical knowledge and collection of documentation sources.
(Oh, by the way, the term is not 'cast bed plate' or 'frame' either, it's just cast engine bed (precisely to discriminate homogeneous one -piece casting from those also-ran 'cast frames'.
As noted in a different context a few days ago, the Trust does have sources with competence in large steel castings, and has gotten estimates for a comparable cast bed -- the problem being that if more than one pour is required, which would not have been too problematic at Granite City where they were set up to crank out hundreds, but is a big thing for one-off production of something this complex and accurate, the cost balloons. Now, it may turn out to be necessary to cast the bed after all, and push the time estimate and funding plan back accordingly. All this is known and discussed, with actual modern foundrymen who don't BS.
I find the endavour to subject a multi million dollar build of a steam engine to the unknown risks of attempting a speed record, which has no reason, nor any value, rather questionable. I can only assume that there is a substantial amount of false pride attached to that.
OvermodYou can carry on with that whole 1940s-knew-best line if you want; this is America and I'm not the forum police.
Whoa! Hold the horses! You are about to derail!
Overmod(Oh, by the way, the term is not 'cast bed plate' or 'frame' either, it's just cast engine bed (precisely to discriminate homogeneous one -piece casting from those also-ran 'cast frames'. This is more than a nit-pick; if you can't even name it right how do you know it's superior to a properly-designed modern fabrication of equal or better engineered characteristics in all axes?
You got me there.
I had just been reading about the antics on the "Foot Plate" of the Mallard and the word plate was stuck in my mind. I won't make that mistake again.
Dummy me
A locomotive bed is a one-piece steel casting for a steam locomotive that consists of the locomotive frame, the cylinders and valve chests, steam pipes, and smokebox saddle, all as a single component. It was a development of the final years of steam locomotive design in the United States. Most large cast-steel locomotive beds were made by General Steel Castings. The advantages included greater strength and more accurate alignment.
My point is still, IF it is a copy then any "tests" of the previous 1945-46 T1s are null and void.
Yeah, I know some of the guys on the trust. Yes, they are good. I go back to the early '80s with Bensman and also worked with Wes Camp a time or two.
I'll be setting aside a little of my stipend to buy the first ticket available.
Cheers, Ed
Its well known between Crestline and Ft.Wayne the T1s hit 90-100 mph on a routine bases in regular service.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
I've seen the arguments about the lack of a solid cast frame before and the mention of how we can never truly replicate it just like Baldwin built the original.
But this is the 21st century, the world of instant communication and self landing rockets. We have materials available that weren't even in labs 50 years ago. There are definitely things we know now that the guys in Baldwin in the 1940's would have killed to know. The extensive Solidworks drawings coming out of the T1 trust are a modern drafting wonder.
It's not like the knowledge of steam locomotives have been lost, physics are still the same laws, math is the same, and countless heritage railway's and modern FRA codes have kept steam locomotive knowledge alive. If anything the resonance of the locomotive can be tested using a Matlab or Python code, a timesaver compared to the hand calculation the original engineers would have done.
Really the only thing that is still in doubt is that pesky frame. If they can find one lost mold casting company with a sand bed big enough, its certainly possible to still cast the frame. However with modern techniques, welding might just be simpler and faster.
And, all of this has WHAT to do with model railroading? Just curious...
Marlon
See pictures of the Clinton-Golden Valley RR
The biggest limitating factor for high speeds are the reciprocating, unbalanced masses, i.e. the valve gear and connecting rods, which rotate at a tremendous high speed, causing the loco to buck like a stubborn bronco, damaging the track and what not. Just imagine one of the side rods breaking ...
The British steam locomotive steam records were judged according to pretty strict objective standards for precision and thus the Brits have always tended to cast shade on steam speeds records which were either more loosely judged in their opinion (I think the NYC's 999 record falls in that category, even though it was intended to be a record breaking run by the railroad itself) or are more purely anecdotal, as some of the Milwaukee Road speed records tend to be. There are also anecdotes about the Pennsy T1 and the speeds that crews hit that the railroad itself would not have advertised or sanctioned or evaluated because the crews were exceeding published speed limits. I recall a story in Trains magazine about a crew that found itself on a work train (!) pulled by a T1 in its final months of service and the engineer basically said "hey watch this" and let her rip.
Just a few years ago the CB&Q E5 streamlined diesel and the Nebraska Zephyr train set had a series of excursions over a weekend on the BNSF line to Quincy IL and back. I watched it go through Mendota IL and it was flying (and as I was putting down my camera I noticed that I was totally surrounded by grass fires set by the hot exhausts -- probably a few decades of carbon buildup were involved!). Given the tangents on that line - the real racetrack of the old CB&Q -- the crew let her rip, maybe forgetting that the engine now had a GPS transponder on it and the dispatcher had access to speed information. Story is that they briefly got it up to 100 on track where Amtrak would probably be limited to 79. Fortunately that track has few grade crossings so the train was in relatively little danger of making a crossing before the gates were down. The DS got on the radio and asked some pointed questions about speed and so that little experiment was ended. I heard about this from folks who were listening on their scanners.
Dave Nelson
Medina1128 And, all of this has WHAT to do with model railroading? Just curious...
Well, they aren't restoring an original, because none exist. They are building a replica, from scratch. So it's a model of the real thing, just in 1:1 scale.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
dknelsonThe British steam locomotive steam records were judged according to pretty strict objective standards for precision and thus the Brits have always tended to cast shade on steam speeds records which were either more loosely judged in their opinion
Dave - you are on the spot there! Mallard´s speed record is quite debatable, as the line had a slide downhill grade. Sir Nigel Gresley himself questioned the record and saw the speed more in the vicinity of 124mph, than the split second tachometer reading which showed 126mph. This would make Deutsche Reichsbahn class 05 002 the fastest steam engine - until PRR T1 breaks it officially.
Should your layout have a stretch of triple track, you can have all those engines race against each other!
Henry
COB Potomac & Northern
Shenandoah Valley
I would rather have seen them put the money and effort in to getting the 1361 running or build a new K4s.
oldline1
Overmod (Don't come to me with fibs about alleged '120mph' 3460 class locomotives or those Milwaukee F7s so suspiciously similar in all respects to the C&NW E-4 that couldn't even get to 100mph with a train; on the other hand Mr. Bruce, who ran Alco and was in a peculiarly good position to know, said the A was easily good for over 128mph ... you'll appreciate where he got that number ... and we owe it to his memory to find out if he was right.)
(Don't come to me with fibs about alleged '120mph' 3460 class locomotives or those Milwaukee F7s so suspiciously similar in all respects to the C&NW E-4 that couldn't even get to 100mph with a train; on the other hand Mr. Bruce, who ran Alco and was in a peculiarly good position to know, said the A was easily good for over 128mph ... you'll appreciate where he got that number ... and we owe it to his memory to find out if he was right.)
F-7 vs. E-4 is ALCO vs. Baldwin and at that point ALCO knew far more about high speed running. You should not dismiss the speed claims about the F-7 so quickly.
As a kid in the early 50's I rode in my Uncle Ed's PRR K-4 at over 100 mph in south Jersey west of Williamstown. Both my dad and I were quite scared and hung on to anything we could find in the swaying and rocking cab. No safety chains, and the loco was hand fired. The roar and power of the draft was quite noticable....all on small flanges. I did not go back for a second ride and settled for my other steam driving uncle...Ike who ran a rather docile Erie K1 on a slow commuter run to Jersey City. It is sort of like my Corvette....don't think about the family jewels just inches above the ground at 90 mph.
I did hear tales of track damge from steam locos at speed so I doubt seriously that any road today would allow a T-1 these speeds. Just a bit off balance...call the track crew at a huge expense.
I have less than no intention of flaming or denigrating Ed, who knows more about historical railroading than I do. It's the attitude that the T1 Trust is 'doing a model railroad build' that has me so hot -- that they'd get a passel of detail drawings and think building the locomotive is just a matter of fabricating everything to scale and screwing it together the way Fine Art Models or Mr. Kohs might do. That was not the design process for any of the generations of duplex at Baldwin, and it is manifestly not the design process at the Trust -- the point is that the public doesn't see the depth or scope of ongoing work in things like multiphysics simulation or working with Lehigh to perfect side-rod alloys and fine geometry. Now, no small part of that has been by intent; you have to be registered to access the repository, for example, or see the extensive discussions conducted over elements of the detail design or fabrication so far. If Baldwin were developing this design today, they would almost certainly use the kind of tools and methodologies the Trust is, and in many cases the result wouldn't have needed the fine-tuning and improvements PRR conducted over the several years after completion (and would have continued with, had the engines not been pulled from first-line service when they were).
Tinplate ToddlerI find the endeavour to subject a multimillion dollar build of a steam engine to the unknown risks of attempting a speed record, which has no reason, nor any value, rather questionable. I can only assume that there is a substantial amount of false pride attached to that.
There's an old saying in the United States about what happens when you ASSume something like that, and I would venture that you have embodied it.
I'll certainly grant you there was a certain element of 'we'll wipe Gresley's nose with this' in the very early days of the effort, when it was much like a bunch of railfans talking about their dream projects, or for that matter Davidson Ward touting CSR/SRI's 'science project' as the exemplar of new reciprocating steam power for Amtrak. In both cases, the bold claims have been, shall we say, officially reduced as common sense comes to the fore. If there is high-speed testing done, the purpose is not to flog the 5550 faster than Mallard, but to determine how well the duplex principle achieves its purpose at high speed -- as Ed said, in the real world and not on a test plant or modeled in a computer. And there are a number of significant ones, including assessment of actual reasons for high-speed slip and confirmation of Chapelon's speculations about lateral rod deflection at speed, that almost must be confirmed empirically whether or not computer models show the behavior.
Most of the perceived future value of the locomotive as a 'capital asset' (aside from its historical value as an embodiment of lost technologies) is as an advertising supermodel, not an efficient or even nostalgic replacement for excursion or passenger power... although there may be a little cachet in 'it goes even faster than it looks'. It should be as useful as any comparably-sized 4-8-4 for those kinds of purpose, up to a much higher useful speed than even an eight-coupled with lightweight rodwork would achieve in the modern diesel era... but in an insurance-limited world, the high-speed-augment question is far less important than the capability of reliably running at road speed, with good stopping and acceleration, and the 'dash' ability to get out of any scheduling situation with minimum inconvenience or delay to prospective host operations. (At which point 5550 has far less augment than, say, 614, which Ross Rowland has repeatly noted was assessed to cause less track damage than its equivalent in contemporary diesels...)
In particular, the Trust did not undertake this project merely to break records, or for that matter to make money in the excursion business (and a good thing it was, too, considering the removal of the Amtrak excuse for allowing excursion traffic!) It's more akin to the original inspiration, the near-total reconstruction (and not incidentally, fixing of various design fehlern and near-certain intentional sabotage) involved with the Duke of Gloucester.
Now, it does have to be added that I would relish wiping the eye of a fairly vast conspiracy of naysayers who have pooh-poohed the thing from the beginning, but it is for the people raising the millions to say how their expenditure is best spent, as it were. Very early on, I mentioned another example of fast-running hubris with a multimillion-dollar asset that came to grief shortly thereafter, in no small part as a result. Any operations will be mindful of these things.
Medina1128And, all of this has WHAT to do with model railroading? Just curious...
I thought the moderators would have at least moved this thread to the Prototype Information category already.
Some of this discussion has rekindled my recollections of other prominent efforts to "modernize" steam technology.
Anyone remember Ross Rowland's ACE 3000?
https://www.american-rails.com/ace-3000.html
and his earlier efforts with C&O 614:
https://www.co614.com/main/history-of-614-2/#.Xe77SehKjRY
How about the Coalition For Sustainable Rail?
https://newatlas.com/csr-project-130-steam-locomotive/22670/
I applaud any effort to resurrect steam technology and apply 21st century advances to it. I wish the good folks at the T1 trust every chance for success.
gmpullmanI thought the moderators would have at least moved this thread to the Prototype Information category already.
That ability has been lost for more than a month now, Ed, along with a number of other forum functions. We'll see if the new promised software next year will address those issues.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
I don't understand the end game for the project and I probably won't be here for the conclusion.
However I would argue that if it is built from plans, with modern materials and upgrades in design, technology or manufacturing, it isn't really a 1:1 model. It's an upgrade. One of Sam Colt's inventions, that I can't mention is currently manufactured in what is called the 3rd generation. John Browning's inventions have been constantly upgraded for more than 100 years and are still in use my the military. The changes are evolutionary.
Unlike other places in the world, high speed rail just isn't a thing in this country. If it ultimately can go 200 or 300 mph, are we going to have high speed steam, or even solar or electric?
Tinplate Toddler The biggest limitating factor for high speeds are the reciprocating, unbalanced masses, i.e. the valve gear and connecting rods, which rotate at a tremendous high speed, causing the loco to buck like a stubborn bronco, damaging the track and what not. Just imagine one of the side rods breaking ...
And yet,PRR engineers would hit 90-100 mph between Crestline and Ft.Wayne even with K4s. Back then railroads and passenger engineers pride theirselves when their crack passenger trains arrived on the advertized.
On the other hand..Should something go afoul the engineer would get the blame citing excessive speed and rule infractions.
I believe some comments were made above regarding the advisability of spending hard earned cash on a T-1 venture, and respectfully, I must ask the question:
So what about the millions of dollars spent each year on automobile racing?
Desiring to make a T-1 live again, and race against time, is a drop in the bucket by comparison. I hope the engineers and technicians succeed!
John
LensCapOnF-7 vs. E-4 is ALCO vs. Baldwin and at that point ALCO knew far more about high speed running. You should not dismiss the speed claims about the F-7 so quickly.
This is a bit strange. In the world I grew up in and the steam community I know, I thought it was well-established that the E-4 is an Alco locomotive, built at about the same era as the F7s and sharing a suspiciously high number of dimensions and construction details with them. We all bend over trying to believe before breakfast that the F7 couldn't possibly have E-4 issues... but barring the existence of magic spells (and for that matter any high-speed testing of the sort that established Burlington Hudsons as over-112mph engines) it becomes increasingly difficult to believe in fairies. (We might also note that Mr. Bruce says nothing about them as notably fast, whereas...)
About the speed and capability of the As there can be little doubt, and were it not for the fact that there is utterly no practical use for one in modern railroading, high speed or preservation, I would have long ago spearheaded some effort to rebuild one. Before the PRR 'standardized' its high-speed future on double Atlantics it was working on an E8 that would have 84" drivers, oil firing, drive on the leading pair, and doubtless show Baldwin's take on the Alco high-speed formula... I hesitate to use the words 'rip off' as there was other similar high-speed design work in that brief period, and PRR was notorious for espousing four-coupleds as the only true high-speed approach (hence the reverence for the Lindbergh Engine), but it does occur to me that NIH was as suspended then as it had been when Alco essentially invented the K4 a couple of decades before...
Tinplate ToddlerDave - you are on the spot there!
Yes, but I humbly submit for different reasons than those which follow...
Mallard´s speed record is quite debatable, as the line had a slight downhill grade.
The effect of which can, and has, been calculated. A far greater reason for debate is how badly the inside big end came apart as a direct result of poor valve-gear drive action at high speed and necessary cutoff. I only excuse it because the detail design was promptly fixed... but then again, the new design was never tested to anything like 125mph.
Sir Nigel Gresley himself questioned the record and saw the speed more in the vicinity of 124mph, than the split second tachometer reading which showed 126mph.
You must have Swiss blood because there are so many holes in this sentence. What Gresley actually accepted was a true peak at 125mph (not for a very long distance on the trace, I think corresponding to something like 150') but not an artifact; he explicitly rejected 126 as demonstrable surge artifact (and said so).
The records were taken with a dynamometer, which comprises a speedometer as part of the instrumentation, but the result was a pen trace and not a needle indication. This is the amateur mistake in that 'low-flying' T1 story that has the speedometer 'pegged at 120mph'. Now, cars have 120mph speedometers, but the T1's Jones-Motrola only read up to 100. Had the author not felt the need to get salty about the instrumentation we could just have believed it was timing mileposts with the ol' 992B... but poof! wrong details instantly ruin verisimilitude.
This would make Deutsche Reichsbahn class 05 002 the fastest steam engine - until PRR T1 breaks it officially.
Personally I think it is difficult to believe an A4 could possibly be faster than an 05 (at least 001 and 002), and we are deprived of explicit proof only because the Germans used the metric system: essentially they 'lifted' after achieving the magic metric two-ton and didn't push that slight additional fraction. (And yes, I do think there was at least some consideration on the English side of ensuring that the numbers would 'beat the German ones') I do have some concern that the draft and firebox were at the verge of having their flow numbers go 'upside down' at that speed and load (cf. the accounts in Gottwaldt of the sirenlike howl at full tilt) but unlike the Mammuts (which are still my favorite German engine despite not performing a needed job as expected) they could likely have been run 'faster than 126' and perhaps even than the "magic" American claim at 127.1 with a little more tinkering. (This despite a careful dynamic analysis by students in Eastern Europe which indicated a likely whopping critical resonance in guiding developing by about 122.5 equivalent mph)
Thing is that the real revolution in achievable high speed was not in higher drivers but in lightweight rodwork, as close to zero overbalance as you could get, good lateral motion, really good steam generation and large internally-streamlined passages, ling-lap long-travel valves with generous diameter, low-back-pressure efficient front ends and so forth. The T1 came along just in time to benefit from much of the insight -- although to this day I think it would benefit from very low overbalance, perhaps at the proportion Voyce Glaze used in the J mains but distributed in the coupled
pair as well -- there is little nosing in a duplex, and with that tender and short stroke little potential issue with surge (and that little amenable to correction with rather small Langer balancers)
Baldwin famously didn't like the poppet valves; Kiefer very famously avoided them on the C1a which was like a common-sense correction of many of the wacky T1 details. (Notable by the way for accomplishing something a comparable Niagara would likely not, going from Harmon to Chicago on one 64-ton coal load). It would be interesting to see what either American or French design 'improvement' would have done if applied to an 05 locomotive... (cue the old Laugh-In Arte Johnson meme, 'veeeery interesting'!)
As to the three-way test-off: if you know how to pry the surviving 05 out of Nuremberg I'll be the first to start agitating for running refurbishment (I believe the '63 work was mechanical and not just cosmetic so there may not be too difficult a time). The British will never, no never (and I do NOT mean 'hardly ever') let Mallard out again, but any good A4 given a Kylchap and the necessary conjugating-gear and bearing beefing up should do as well.
The niggling problem is that they won't survive tech inspection at Pueblo unless very careful instrumentation can be applied to lightweight spoke drivers. There are relatively easy answers for Boxpok or Baldwin Disc centers, but spokes are likely going to need so many strain gages and microphones for the 'necessary' speed and load range as to make data communication alone an interesting exercise.