Anybody tried DCC and went back to DC?

Greg Pollard. wrote:
>>>>> Time Table and Train Order control systems were demonstrated >>>>> to not work safely in isolation during the 19th century,
>>>>> where multiple trains are sent into uncontrolled sections >>>>> without any further safeguards. There has to be some further >>>>> safeguard, which you are apparently ignorant of. >>>> >> Of course this inadequate system (Dispatcher + Time Table + Train >> Orders) was used quite successfully for over 50 years. > > "Successful" is very subjective...
Well, that's the first sensible thing you've written in this thread. You, sitting in your bach in New Zealand, running and pranging your models with a computer, think it's unacceptable. The North American railroads, in the real world, running real trains with real people, disagreed. Get over it!
> The system cannot guarentee to keep trains separated in normal usage, > let alone fail safe or cope with normal human oversights or > failures.
No system can *guarantee* to keep trains separated in normal usage. Like any sytem, TT/TO worked most of the time. > > You gave two examples of rules and I've shown you where they fail.
You gave two very silly, ill-thought-out hypothetical examples which are not borne out by real-world experience.
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TT/TO doesn't separate trains - one train per block operation does.

Whatever - I'll be away for a couple of weeks so you're going to have to be nice to Terry if you want to talk to anyone.
See you, Greg.P.
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Greg.P. wrote:
>> No system can *guarantee* to keep trains separated in normal usage. >> Like any sytem, TT/TO worked most of the time. > > TT/TO doesn't separate trains...
What evidence do you have to support that assertion, Procter?
> ...one train per block operation does.
Really? So by your "reasoning", permissive block working cannot separate trains, either?
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The evidence is obvious - the separation is purely of time and human senses. - For time to infallibly separate two trains, the separation needs to be longer than the traverse time of the section. - for human senses to infallibly separate two trains, the speed must be restricted so that stopping distances are less than the distance able to be travelled within the limitations of those human senses.

See above factors.
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Exactly how can one supply evidence that something isn't? The very rules surrounding TT/TO operation show that it doesn't separate trains, other than at the point and time of departure.

Train separation needs to work in EVERY instance, not just in general. ONE train smash is too many.

Try reading accident reports.

Permissive block working is only allowed in very specific circumstances where other safety factors come into play.
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Greg.P. wrote:

Mark the expert is still ignoring the hard evidence at http://www.du.edu/~jcalvert/railway/trainord.htm
'Failures of the train order system can be classified in three natural categories: (1) improper creation of orders; (2) failure of delivery of
orders; and (3) misinterpretation or overlooking of orders, corresponding to the dispatcher, operators and train crews.'
'The dispatcher is the key person in the train order system, and the only one whose work is not checked or monitored.'
This is a major weakness of TT/TO systems used in the steam era. Mechanical interlocking and the absolute block systems eliminated this and the communications weakness of the TT?TO system. That's enough reason to show Greg is correct.
J. B. Calvert notes there were 68 accidents under the American system of time table and train orders from ICC reports, 1911-1966, that main cause was a failure of the TO/TO system.
I am still waiting for Mark the expert to provide an apology to Greg and other readers who have been mislead by his inaccurate, uninformed statements in this thread.

About one a year in the US due to TT/TO failure.

Plenty of references at http://www.du.edu/~jcalvert/railway/trainord.htm

That's correct Mark. Absolute block is safer than permissive block. 2 different systems. That is why permissive block working was not permitted for passenger trains on many railways where both systems operate.

Permissive block working is different to absolute block working Mark. Don't cloud the issue. Greg uses absolute block on his layout.

Greg's correct again.
Terry Flynn
http://angelfire.com/clone/rail/index.html
HO wagon weight and locomotive tractive effort estimates
DC control circuit diagrams
HO scale track and wheel standards
Any scale track standard and wheel spread sheet
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<snip>

<snip>
At the risk of clouding this issue, which is already pretty milky, have either of you gentlemen ever heard of "smoke orders"?
In the early days of railroading, the head enders kept a keen watch for smoke in the distance, which might indicate the presence of an oncoming train. Absent smoke, they continued to run.
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Sure I've heard of it but it's just a lot of hot air - don't you have wind in the USa? ;-)
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NSWGR wrote:

Except of course that you didn't get to be a dispatcher without YEARS of training and testing.
Except of course that there is a complete written record of every train order issued by a dispatcher, both at the dispatchers desk and at every operators desk that copied the orders.
Except of course that the UCOR (Uniform Code of Operating rules) embodied the experience of decades of running trains and was updated regularly if experience indicated that there were loose rules.
Those who claim that interlocking removed all the problems haven't looked at the horrendous accidents that occurred because train crews blindly believed that the signals were correct. Interlockings introduced all their own accident causing problems some of which were only found when there was an accident.
NO method of train control is without its flaws. NO method of train control is perfectly safe. They are all subject to human or mechanical failure.
NO method of train control is suited for all situations. A full mechanical interlocking that is suitable for a small country like England*1, does not work in Canada with Thousands of miles of track. Similarly T&TO does not work in an area with dense traffic; some version of interlocking is needed.
Bill Dixon
*1 For those of you who would complain about the comment that England is a small country, I would remind you that in Canada at their most grandiose point, the James Bay Power development planned to make a man made lake big enough to put England in with room to spare.
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Bill Dixon wrote:
>> 'The dispatcher is the key person in the train order system, and >> the only one whose work is not checked or monitored.' > > Except of course that you didn't get to be a dispatcher without YEARS > of training and testing.
> Those who claim that interlocking removed all the problems haven't > looked at the horrendous accidents that occurred because train crews > blindly believed that the signals were correct. Interlockings > introduced all their own accident causing problems some of which were > only found when there was an accident.
You're wasting your time, Bill. Procter belonga to that peculiar group of people who believe they are the font of all wisdom, unimpeachable authorities on *ANY* subject - regardless of how little they actually know.
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Yeah yeah, whereas Mark really is "the font of all wisdom, unimpeachable

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Hmmmm, that would indicate experience is a positive factor. If your system is reliant on experience then there's a definite human factor involved, humans are notoriously unreliable!

Yep, written copies will positively keep trains apart! (if you can get a big enough filing cabinet between them during incidents)

Incorrect: Human failures can be covered by automatic braking systems. Mechanical failures (of fixed plant) are largely covered by "failsafe" systems.
That of course still leaves mechanical failures of rolling stock and track, but they equally affect TT/TO and block systems.

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Greg.P. wrote:
>> Do you not understand what evidence is, Procter? I didn't ask for >> more of your opinion, I asked for evidence. > > Exactly how can one supply evidence that something isn't? The very > rules surrounding TT/TO operation show that it doesn't separate > trains, other than at the point and time of departure.
And at the point and time of arrival. Separation is maintained, trains pass safely.
>> If, as you stupidly keep asserting, "TT/TO doesn't separate >> trains", there should be countless hundreds of thousands of >> accident reports, from the collisions that ensued every time an >> attempt was made to run multiple trains under TT/TO. > > Train separation needs to work in EVERY instance, not just in > general. ONE train smash is too many.
Yep, one prang is too many. So we'd best disregard block systems, since they too have allowed collisions.
>> Where are they? Where is the unassailable evidence that trains >> cannot be separated and run safely??? > > Try reading accident reports.
Unlike you, I have. And unlike you, I have the professional knowledge and experience - something you'll *NEVER* have - to understand the lessons they contain. But I should have guessed you's squib that answer, because there is no evidence to support your argument.
>>>>> ...one train per block operation does. >>>> >>>> Really? So by your "reasoning", permissive block working cannot >>>> separate trains, either? >>> >>> See above factors. >> >> See above nonsense! Funny then, that permissive block working is >> also in widespread use throughout the world, even Germany. > > Permissive block working is only allowed in very specific > circumstances where other safety factors come into play.
In Germany, perhaps. Elsewhere, it's a common system, used in a variety of circumstances. The main "safety factors" being, yet agin, rules and procedures...
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Care to explain to me how separation is maintained between two trains, one following the other, when the only separation mechanisims are departure separation and a flagman's discression in dropping flares??? Think Mark, think!

No Mark, they do not "allow" collisions. They have to be over-ridden for collisions to occur.

I'd say that the collisions that have in the past and that still occur under TT/TO practices over-rule your point in regard to my lack of experience.

I'm well aware of it's use, particularly on Wellington region commuter services here in NZ. I was close friends with a signal engineer who had been involved in it's set-up and upgrading 1955-80.
Regards, Greg.P.
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Bill Dixon wrote:
>>>> Time Table and Train Order control systems were demonstrated to >>>> not work safely in isolation during the 19th century, where >>>> multiple trains are sent into uncontrolled sections without any >>>> further safeguards. There has to be some further safeguard, >>>> which you are apparently ignorant of.
> Of course this inadequate system (Dispatcher + Time Table + Train > Orders) was used quite successfully for over 50 years.
You're wasting your time, Bill. Procter - the Vicky Pollard of r.m.r. - will never concede that TT/TO was used successfully throughout the USA for mnay years. His knowledge of these matters is far greater than yours - he once had a friend who spoke to someone who had a friend who travelled by train once - so he speaks with authority when he says it can't work...
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We're discussing a hobby or passtime that has almost no relevance in the big wide world - or did I miss the annual model railway Oscar prize night? ;-)

So why exactly are you continuing to attack me for stating that I am one of those who fit the subject line? The original poster asked a question and I responded. Quite simply, DCC has operating limitations. If you never come up against them then that's nice, but don't rubbish people who do.

Sigh! - one is forced to identify individual locos to be able to operate them. - all one's loco roster needs conversion at once for DCC to be used. - one needs to drive every locomotive. - cost.

Hmmm: - constant lighting was the biggy when I started into electronics. (1960s-70s) It's easily achieved in a number of well defined ways. - switchable constant lighting. Add-on to the above. - sound - see Puget Sound system. (c 1970) - speed setting/mapping. Either onboard or within controller.
A "decoder" within an analogue controlled loco is quite practical, capable of speed mapping and light/function switching. There's something like it reviewed in one of the US mags very recently.

You making an unsubstanciated comment doesn't amount to evidence. Yes, there are situations where a train may move forward into an occupied block in Germany, but they are very specific circumstances.

About as frequently as you need reminding that the World is not the USa.

I tend to assimilate information about people I like or agree with or who show themselves worth of respect.

a: where in "rec.models.railroad" does it say "USA"? b: where does it say DCC only relates to the USA?
North American rules and procedures are

Wow, let's not confuse people with alternatives!
Whether

Sorry, but there are US railroads that use or have used block control. There are US modellers who use hidden staging yards. There were US railroads that didn't paint 3 foot high reporting numbers on their locos.

Life is odd.

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Greg.P. wrote:
>>> DCC isn't the only way to achieve many of the functions available >>> at the outputs of loco decoders, but unfortunately most >>> electronics producers have jumped on the DCC bandwagon and >>> totally ignored the other possibilities. >> >> And they are? > > - constant lighting was the biggy when I started into electronics. > (1960s-70s) It's easily achieved in a number of well defined ways. - > switchable constant lighting. Add-on to the above. - sound - see > Puget Sound system. (c 1970) - speed setting/mapping. Either onboard > or within controller.
All of which are interesting, but to me they are not important features of DCC. They're nice, but not vital. To me, the greatest advantage of DCC is that it frees you from the artificial and unrealistic restrictions of electrical blocks.
>>> Block control is normal on most railways of the world. >> >> Pig's arse it is. But since you display a profound ignorance of how >> railways actually operate, I'm not surprised that you think that. >> I notice you didn't address my comment about German operating >> procedures allowing more than one train per block, either. Or are >> you just going to ignore any evidence that contradicts your >> position? >> > You making an unsubstanciated comment doesn't amount to evidence. > Yes, there are situations where a train may move forward into an > occupied block in Germany, but they are very specific circumstances.
Exactly as they are in other systems of safeworking. The fact remains that such circumstances are allowed for, but your system doesn't.
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I'm modelling European railways, where slightly over 50% of the trains are passenger and are lit much of the time. Constant lighting is a biggie for me.
To me, the greatest advantage of

Sure, but I'm modelling a prototype that used signalling blocks to achieve the highest practical usage of it's main line. If I already have to block my track electrically for detection and signalling then your "greatest advantage of DCC" is negated.

Situations where more than one train is allowed per block are specific exceptions, allowed for and controlled by specific rules. Almost any rule has exceptions. In German railway practice any exception has it's own rule. =8^)

I'll admit that my command of German is not fluent and that my understanding of the rules I apply to my specific modelled prototype are somewhat labouriously translated. However I'm confident that I have applied (almost :-) all the relevant ones. On my mainline there are no normal situations where one train should enter a block already occupied by another. Exceptional circumstances have another set of rules to be applied, and there DCC would have an advantage over my block electrical system. I'm quite happy to ignore the possibilty of such exceptional circumstances as they would add very little to the potential of my layout.
Operations within station confines are another matter which I addressed reasonably fully in another post.
Regards, Greg.P.
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Greg.P. wrote:
>>> DCC isn't the only way to achieve many of the functions available >>> at the outputs of loco decoders, but unfortunately most >>> electronics producers have jumped on the DCC bandwagon and >>> totally ignored the other possibilities. >> >> And they are? > > - constant lighting was the biggy when I started into electronics. > (1960s-70s) It's easily achieved in a number of well defined ways. - > switchable constant lighting. Add-on to the above. - sound - see > Puget Sound system. (c 1970) - speed setting/mapping. Either onboard > or within controller.
All of which are interesting, but to me they are not important features of DCC. They're nice, but not vital. To me, the greatest advantage of DCC is that it frees you from the artificial and unrealistic restrictions of electrical blocks.
>>> Block control is normal on most railways of the world. >> >> Pig's arse it is. But since you display a profound ignorance of how >> railways actually operate, I'm not surprised that you think that. >> I notice you didn't address my comment about German operating >> procedures allowing more than one train per block, either. Or are >> you just going to ignore any evidence that contradicts your >> position? >> > You making an unsubstanciated comment doesn't amount to evidence. > Yes, there are situations where a train may move forward into an > occupied block in Germany, but they are very specific circumstances.
Exactly as they are in other systems of safeworking. The fact remains that such circumstances are allowed for, but your system doesn't.
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Analogue control with an in-loco decoder able to be addressed by overlaying traction current with a digital command to switch the usual functions but also including on/off control of traction current. All this would involve in regard to (most) present day DCC decoders is a change of programming. The control equipment would be a little more complicated, involving a DCC command generator intervening between the analogue output and the track.

There's (one of) our points of difference - the restriction of blocks is prototypical on many railways whereas the "advantage" of DCC is contradictory to block control.
Regards, Greg.P.
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