Overmod, I was actually thinking of the radios that could be used whether you had AC or DC power coming into your house. The heaters of the tubes were wired in series so you did not need a transformer to provide that power, and a half-wave rectifier was wired in so that DC would flow right through it to provide amplifying power. The standard arrangement was three tubes with 12.6 volt heaters. one with a 35 volt heater (rectifier), and one with a 50 volt heater (output). This arrangement of tubes was called "The All-American Lineup."
Johnny
BaltACD 243129 Way to go fellas, 'mob up' and derail the thread. Congratulations on your success. The time honored internet forum tradition of thread jacking. Nothing new. Just as time honored as the Old Foggy hollering 'Get off my Grass!'
243129 Way to go fellas, 'mob up' and derail the thread. Congratulations on your success.
The time honored internet forum tradition of thread jacking. Nothing new.
Just as time honored as the Old Foggy hollering 'Get off my Grass!'
Who are you kidding? It is not a time honored tradion here. It is petty and vindictive for the purose of getting even with someone or wrecking some topic that you resent. Time honored tradition--give me a break.
BaltACDJust as time honored as the Old Foggy hollering 'Get off my Grass!'
What's an "Old Foggy"?
243129Way to go fellas, 'mob up' and derail the thread. Congratulations on your success.
Never too old to have a happy childhood!
Way to go fellas, 'mob up' and derail the thread. Congratulations on your success.
Thanks to Chris / CopCarSS for my avatar.
243129 Overmod That's not pointed at you, but you're welcome to sing with us if you like. Thanks but I'll pass.
Overmod That's not pointed at you, but you're welcome to sing with us if you like.
That's not pointed at you, but you're welcome to sing with us if you like.
Thanks but I'll pass.
No surprise
Overmod Hey fellas, sing along with Idina and me! https://www.youtube.com/watch?v=L0MK7qz13bU
Hey fellas, sing along with Idina and me!
https://www.youtube.com/watch?v=L0MK7qz13bU
Et tu Mr. E.?
DeggestyA little closer to today--explain the value of a radio that could run on both AC and DC power.
What's hard about that? If you're going to spend 'that kind of money' for a radio, you want something that you can use 'in the field' on dry-cell batteries and not just plug in. And, before the rural electrification push in the Thirties, in the days when 'off the grid' was not a good thing, there were a relatively large number of people who did not HAVE AC, and were either on the early equivalent of gensets or used battery power 'trickle-charged' from things like Aermotors. See also the large "DC" market below...
Don't mistake the 'transistor radio' for being the first portable. Bill Lear made his start making 'portable' radios of another kind, small enough to install in a car. He was told that was 'impossible' because contemporary tuning capacitors couldn't be minimized below a certain point -- he simply inserted dielectric sheet between the (smaller) plates and bingo! the Motorola was born.
The first radio I built was a crystal set that connected to the house plumbing for an antenna. You 'tuned' it by moving a pointed wire from place to place on the crystal looking for 'just the right spot'. If I remember correctly, I sent away for the 'kit' including the crystal, but for the life of me I can't remember where. Not younger than four, not older than eight.
The value of tube amps is their lavish ability to push electrons -- enormous current boiling off those hot filaments. The bane of any audio amp that is working with a complex audio signal (the effective envelope of which can be thought of as superposition of a bunch of sine waves of different amplitude and period) is a problem called 'clipping', where the amp has insufficient power to drive the amplitude high enough and it becomes a square wave, with the associated impulse noise around the transition -- you don't have to be an audiophile to hear that, and dislike it! When tube amps do clip, they do so more smoothly, more 'like a complex sine wave', and this contributes to perceived musical sound quality at high output.
Many people also like the 'warmer' sound in midrange that the tube amps provide by being slightly less precise in duplicating fast transitions in that range.
Of course, a great deal of this is snobbery, and I suspect that's mostly what influences the 'tube recording amp' idea. I'm sure it's possible to make a good tube amp to drive a Scully lathe -- after all, that's what generations of people in the recording industry used -- but that's less an audio amp than a specialized load-following circuit, and I suspect one where excess drive current is not as 'useful' in preserving fidelity as when you're driving a relatively undamped solenoid coil to generate sound waves.
My own opinion is that it's better to sample digitally at a high enough frequency (more than 2x the highest frequency to be reproduced out of the DAC, ideally much more - 'industry standard' in the field is 96kHz and I use 192) especially since digital storage has become so cheap. Then use a really good DAC that can shape the output waveform as desired, without distortions or clipping, and feed that into your fancy hybrid amp.
Mr. Klepper is an expert in this field and I look forward to his thoughts and discussion.
I'm gong to go back a little farther--the first radio my family had was a crystal set my oldest brother built.
A little closer to today--explain the value of a radio that could run on both AC and DC power.
tree68 zugmann Vinyl is really making a comeback, and yes, even millenials are buying. I've also read that tube amps are again becoming popular. Much richer sound that solid state/digital.
zugmann Vinyl is really making a comeback, and yes, even millenials are buying.
I've also read that tube amps are again becoming popular. Much richer sound that solid state/digital.
zugmannVinyl is really making a comeback, and yes, even millenials are buying.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Murphy SidingCertainly, but try to find anyone under about 35 that knows what a skipping record is.
Vinyl is really making a comeback, and yes, even millenials are buying.
https://www.classicfm.com/discover-music/millennials-are-going-nuts-for-vinyl-revival/
It's been fun. But it isn't much fun anymore. Signing off for now.
The opinions expressed here represent my own and not those of my employer, any other railroad, company, or person.t fun any
Murphy Sidingtry to find anyone under about 35 that knows what a skipping record is.
Are they mesmerized watching the between-channel snow on old tv sets? Perhaps a little intrigued by the horizontal and vertical hold controls, wondering why anyone would want to intentionally distort their picture that way? Puzzled over how my gas refrigerator continues to work even during a power failure?
https://www.youtube.com/watch?v=7nEYWwCsdUY
Murphy Siding My kids wouldn't even know what that reference means and they're all 3 in their 20's
Murph,
I'll bet even your 20 something year old kids realize that if you want to change someone's mind you have to make a persuasive counter argument, and not by repeating that you disagree over and over again.
zugmannIt would be entirely reliant on completely accurate and updated consists being in the system. Which in part are reliant on an ever-shrinking presence of people to input said data.
This actually isn't what I meant by 'reporting the rear end of the train'. It could clearly be done, and PTC functionality backstopped, as Jeff indicated (by using the same sort of offset based on stretched length that we've discussed for the timing function in systems like Leader) but I was actually thinking of something much more direct than 'derived position' or GPS-at-the-rear reported through the connected infrastructure and data communications.
If you're familiar with the old QNS&L's approach: they used simple proximity transponders that let you know increasingly urgently when 'two locomotives were approaching each other'. What I'd do is simply use a dedicated frequency and modulation beamed as partial omni from the EOT, perhaps with time-of-flight clocking as in LIDAR (which can be made accurate to millimetric precision with modern cores) which will assuredly not suffer from loss-of-signal concerns in the range of distance corresponding to restricted speed invocation. Comparable receiver (or selectable function via software enablement in the SDRs) for the 'other locomotives' doing transception and perhaps differential relay.
This is essentially a beacon for the EOT, a radio equivalent of that blinking red light. Not intended to replace a calculated position, or even one that is 'accurate' for train location, early detection of break-in-twos or changes in overall slack, etc.
Besides, a restricting signal is not just for a rear end of a train. There are many other reasons you can have one. Hence why I refer to it as "creepy-crawly speed".
One of my favorite projects was implementing a 'haptic space' achieved by rotary-scanning high-resolution cameras and sensors like the beam from a KCS-style rotating 'safety' light, and using this as a combination HUD and machine vision for nighttime and restricted-vision situations. This would give a little advanced warning of situations requiring 'stop within half range of vision' as well as continuous guidance when actual train speed compared with estimated braking characteristics indicated the train was starting to inch up on what a normal full-service application would produce.
Even then, as you note, there are reasons why being able to stop ASAP is not limited strictly by what you can see. And it is not likely, short of a good autonomous control system, that you'd see automatic 'penalty braking' every time the system thinks it sees something dangerous and 'acts before the crew' directly on the rotair valve or whatever. So there would be plenty of times that the crew goes at full 'creep and crawl' sloth, or that they get nagged by the automatics to do so a tad more slothfully.
All of which I'm on board with no matter how it screws up my vision of high-speed low-latency point-to-point railroad service. Safety first, last, and always.
zugmann Overmod Far more alarming is the litany of things the multibillion-dollar PTC "1.0" overlay boondoggle fails to do in this situation ... one of the few places, in fact, that it ought to function as positive train control. You'd think someone in the government would have learned from the misprogramming at NAJPTC that recognizing and tracking the end of the train is as important as the front. Now everyone can try playing catch-up-ball, spend more money, impose more restrictions ... and perhaps in the end we will get a system that will actually stop a train short of one standing on a main line. What a concept! It would be entirely reliant on completely accurate and updated consists being in the sytem. Which in part are reliant on an ever-shrinking presence of people to input said data. Besides, a restricting signal is not just for a rear end of a train. There are many other reasons you can have one. Hence why I refer to it as "creepy-crawly speed".
Overmod Far more alarming is the litany of things the multibillion-dollar PTC "1.0" overlay boondoggle fails to do in this situation ... one of the few places, in fact, that it ought to function as positive train control. You'd think someone in the government would have learned from the misprogramming at NAJPTC that recognizing and tracking the end of the train is as important as the front. Now everyone can try playing catch-up-ball, spend more money, impose more restrictions ... and perhaps in the end we will get a system that will actually stop a train short of one standing on a main line. What a concept!
It would be entirely reliant on completely accurate and updated consists being in the sytem. Which in part are reliant on an ever-shrinking presence of people to input said data.
Unless the restricted speed condition is set up as part of a structured test. Then you're being maliciously compliant if they think you're going to slow.
Jeff
I don't think the events happened the way the Railway Age article says they did. I think the J B Hunt containers were on the moving train on the adjacent track. The empty oil train rear ended the stopped intermodal train, but most of those cars appear to have derailed away from the adjacent track. (It's hard to tell about the cars ahead of those on there side towards the top of the second picture. Some may have indeed derailed to the inside.) The engines, however, do appear to have nosed toward the inside, between the tracks and caused the other train to derail.
I would like to know how fast they were going, too. Going around that curve, with a train on the adjacent track, sight distance would probably be 3 or 4 cars. PTC enforces the restricted speed, but the high end of it. Ours will start alerting at 18 mph and will make a penalty application at 21 mph. Because current PTC doesn't protect the rear end of trains ahead in restricted speed conditions, engineers are required to be stop tested under PTC RS conditions.
While integrating EOTs and rear end DP units is a good idea, I'm not sure I would depend on them always communicating their location. Intermittant comm loss is an almost everyday occurrance. Sometimes it's the location, some spots are worse than others, and sometimes it's equipment (antennas, wire connections, etc) related. Usually, the comm loss is minor, but if it's going to fail you know it will probably fail at the worst possible time. (Remember the runaway out in Wyoming.)
Since the "back office" is supposed to know where all the trains are and their lengths, I would think following trains could be alerted to where the end of the train ahead is by the back office calculating where the end of the train is. I would add a safety factor to the length of each train, say 500 feet, to allow for mistakes in entered train length.
The RA article is somewhat wrong about hand throw switches in signalled blocks with PTC overlayed. It's true PTC doesn't know their position, but it knows their location. If you're operating under restricted speed conditions, it won't let you pass a facing point hand throw switch without verifying the position of the switch on the PTC screen. Now, if you're already past the governing block signal for that block, and someone opens a hand throw switch (or a rail breaks) within that signal block, you're SOL. Current overlay PTC won't notice the change. (Remember Stanwood, IA last June.)
PTC has it stands, is pretty good. It has it's short comings. Most of those of us that work with it know what they are. (It's amazing to find those above field level managment who don't know about the limitations of current PTC.) However no one with the power to do anything seems to want to talk of them. While PTC is being upgraded, I've never heard of any schedule to take it beyond just being an overlay, or at least integrating more items (switch position, etc) into it.
And, sometimes, good hiring, vetting, training, and supervision still results in accidents and fatalities. The deadliest aviation accident in history was caused by an accomplished and respected 20 year veteran pilot who was the head of the airline's flight training department. Still made a mistake and tried to take off on an occupied runaway, killing almost 600 people....
243129 tree68 There's alot of inertia there - The westbound consisted entirely of empty crude oil tanks. Speed seems to be a factor.
tree68 There's alot of inertia there -
The westbound consisted entirely of empty crude oil tanks. Speed seems to be a factor.
3250 tons is nothing to sneeze at. That's assuming 100 cars at 65,000 pounds tare per car.
Speed was certainly a factor - too fast for conditions - but getting those 3,250 tons stopped was the challenge.
From the article:
The current version of PTC, which is mandated to be fully implemented in the U.S. by Dec. 31, 2020, does not, through an EOT (end-of-train device), determine the position of the rear of a train and transmit that telemetry to a following train via the wayside and central office PTC equipment.
Such features as described above may be incorporated into the next generation of PTC, so-called “PTC 2.0.”
Will this next version 2.0 also be mandated?
OvermodFar more alarming is the litany of things the multibillion-dollar PTC "1.0" overlay boondoggle fails to do in this situation ... one of the few places, in fact, that it ought to function as positive train control. You'd think someone in the government would have learned from the misprogramming at NAJPTC that recognizing and tracking the end of the train is as important as the front. Now everyone can try playing catch-up-ball, spend more money, impose more restrictions ... and perhaps in the end we will get a system that will actually stop a train short of one standing on a main line. What a concept!
Intermodal cars derail pretty easy. I had a broken rail take 10 of mine off the rail, and I was only going 8mph.
And we also don't know how many were knocked off in the initial rear-end collision, vs how many the passing IM train kicked off.
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