gregc ROBERT PETRICK How is signal logic programmed into the DC system? Obviously, I need to study up on how relays function, but for now I'm just looking for the short answer. doubt the logic is any different. isn't the question how is occupancy detected? would such a system need to latch occupancy so that the occupancy condition remains active when DC power is dropped to stop a loco? "un-latched" when DC power is present but a block is not occupied i thought Sheldon's relay nodes handled this, but i don't don't see where block detection is either done or an input in an schematic (DWG #C-002) i have. hopefully Sheldon can provide a brief explanation
ROBERT PETRICK How is signal logic programmed into the DC system? Obviously, I need to study up on how relays function, but for now I'm just looking for the short answer.
doubt the logic is any different. isn't the question how is occupancy detected?
would such a system need to latch occupancy so that the occupancy condition remains active when DC power is dropped to stop a loco? "un-latched" when DC power is present but a block is not occupied
i thought Sheldon's relay nodes handled this, but i don't don't see where block detection is either done or an input in an schematic (DWG #C-002) i have. hopefully Sheldon can provide a brief explanation
OK guys, you asked a lot of questions today and I was busy visiting my 91 year old mother who is an hour drive away.
Be patient and I will take the questions in small bites.
OK, the signaling is a separate "layer" of wiring, a term Robert will be more than familiar with. But it uses different contacts on the same relays that throw and route control the turnouts.
Next, forget you ever heard the term "latching relay" - they are not used in my system for ANY reason. Relays are better "latched" with holding circuits rather than twin coil latching relays.
At any given monement in time on my system, 30% of the relays are energized and held by a holding circuit, and will stay energized as long as needed. They are rated for continuous duty.
Historic side bar - long before DCC put a constant voltage on the track there were a number of detection circuits that detect locomotives, lighted cars and in some cases resistance wheelsets when the DC propulsion circuit is at zero volts. Just look up Twin T, NMRA detection, etc.
I use inductive detectors that are totally isolated from the propulsion circuit. They will detect parked or moving locomotives and lighted cars. They will not detect resistance wheel sets.
To detect equipment with the propulsion circuit off, there is a high frequency single superimposed on the track that will not move the train, or light a lighted car, and that does not interfere with the Pulse Width Modulated speed control signal, but will trip the detector.
When blocks are turned off, not assigned to a cab, the high frequency signal is still on the rails - the detectors still work.
I will cover more in the next installment - we will get into the signals.
Sheldon
ROBERT PETRICKdesign and build a fairly complex, high-functioning layout using concepts and materials available in the DC universe?
i think that's an interesting question. Sheldon has an approach that works for him an presumably a small # of operators. i'm curious about other possibilites.
the answer depends on the # of operators.
presumably not so hard for just a few if one is switching a yard, another running a train on the mainline and another switching a way-freight and possibly work some branch or around the mainline train. the way-freight and mainline may need to share blocks if single track. presumably not with double track. these are my guesses, i'd be interested in hearing from others who have operated such a layout
the one large home layout i know of in new jersey just had tower operators; eight tower operators and dispatcher that configured routes and blocks thru their area and controlled multiple trains with a number of local throttles as the train passed thru.
see chairs in diagram below for locations of towers
after converting to DCC, there is just a dispatcher and 3 tower operators who just align routes. operators control trains using nce throttles. there was an effort to incorporate the remaining towers into the dispatcher, but it was becoming apparent that it would be a lot of work for a single person
i recently spoke with someone having a lot of operating experience who said op sessions having many operators included a dispatcher for aligning mainline routes while way frieght operators could control turnouts with a dcc throttle, but that all turnouts, routes affecting multiple turnouts, could be controlled with throttles if there wasn't a dispatcher
greg - Philadelphia & Reading / Reading
I joined this discussion with the aim of answering a nagging question: can a guy . . . you know, about my height . . . who has no background or experience with model railroading (but with a modicum of brains and possessing sharp eyesight and steady hands, and has some space available and a little discretionary income) take up the hobby in early middle age and design and build a fairly complex, high-functioning layout using concepts and materials available in the DC universe? The answer is starting to look like “No, he can’t”. Roundy-roundy Christmas tree layout? No problem, can do. 4x8 Daytona-style oval with a couple of parallel sidings and maybe a small stub yard? Easy. Full basement (or, in my case full double garage) layout that can be operated in semi-prototypical or freelanced prototypical fashion? Probably not. Sheldon says there’d be a learning curve. Naturally. But does that curve require going back to school for 2 or 3 years to pursue a BS degree in electrical engineering? Not likely.
I could get behind the idea of designing and building a full-blown DC layout just to see if it can be done. I’ve been off on that sort of tangent many times in my life. I would look at the adventure the same way I’d look at the idea of building a speedboat from old-growth mahogany and maple. It’d be a beautiful boat. It’d be elegant and graceful. It’d be comfortable. It’d be nostalgic. It’d be expensive and take a very long time to build. But it’d never win a race against modern boats.
LINK to SNSR Blog
ROBERT PETRICK Maybe I should not chime in and post anything or ask any more questions until I have read and absorbed what has been already discussed.
at this point, i wouldn't bother.
i like you comments, they're focused on the differences in controlling a DC vs DCC layout. this thread is classic in that it has addressed so many topics, but as discussed in the "culture" thread, because of that, it's now a poor source of information -- exactly for the reason you stated above.
in order to help you get on track i didn't just say sheldon mentioned this, but i found and copied the post to keep the current discussion collected(?)
i'm interested in what you have to say, as well as curious what sheldon might add
gregc ROBERT PETRICK What if there is DC power in the next block, but that power was put there by the operator up ahead? What's to stop my train from running over the insulated gap in the rails only to receive power and voltage based on the other guy's throttle knob position? ATLANTIC CENTRAL Because my system does not use common rail, and because each throttle has its own independant power supply, the simple act of staggering the north and south rail gaps between blocks by a distance equal or greater than the typical locomotive length creates a dead zone between the two blocks that are assigned to different throttles. So trains cannot over run their block and then be under control of a different throttle currently controling the next block.
ROBERT PETRICK What if there is DC power in the next block, but that power was put there by the operator up ahead? What's to stop my train from running over the insulated gap in the rails only to receive power and voltage based on the other guy's throttle knob position?
ATLANTIC CENTRAL Because my system does not use common rail, and because each throttle has its own independant power supply, the simple act of staggering the north and south rail gaps between blocks by a distance equal or greater than the typical locomotive length creates a dead zone between the two blocks that are assigned to different throttles. So trains cannot over run their block and then be under control of a different throttle currently controling the next block.
So trains cannot over run their block and then be under control of a different throttle currently controling the next block.
ROBERT PETRICK Something determines that the block is occupied. Something else takes that info and decides to make something else cause the top light of the signal mast to shine GREEN and
it's easier to break this into parts:
in what i'm doing, the processor controlling the signal may not be monitoring all the block detectors that affect the signal. block occupancy is communicated between nodes.
ROBERT PETRICKWhat if there is DC power in the next block, but that power was put there by the operator up ahead? What's to stop my train from running over the insulated gap in the rails only to receive power and voltage based on the other guy's throttle knob position?
sheldon has an interesting solution
ATLANTIC CENTRALBecause my system does not use common rail, and because each throttle has its own independant power supply, the simple act of staggering the north and south rail gaps between blocks by a distance equal or greater than the typical locomotive length creates a dead zone between the two blocks that are assigned to different throttles. So trains cannot over run their block and then be under control of a different throttle currently controling the next block.
on a club layout, there were short stopping block powered thru a relay just ahead of a signal. a relay was opened, dropping power if a train entered the block when the signal was STOP
gregc doubt the logic is any different. isn't the question how is occupancy detected?
Maybe 'logic' was a poor choice of words. Maybe 'schema' would have been better. Something determines that the block is occupied. Something else takes that info and decides to make something else cause the top light of the signal mast to shine GREEN and a third something else to cause the bottom light of the signal mast to shine RED, and if the conditions are right then a fourth something else puts power and voltage into the rails that matches the level of power and voltage of the previous block.
Yeah, and this is kinda the whole egg in a nutshell about DC powered systems. What if there is DC power in the next block, but that power was put there by the operator up ahead? What's to stop my train from running over the insulated gap in the rails only to receive power and voltage based on the other guy's throttle knob position?
Please keep in mind that I know pretty much nothing about DC systems. Apologies for the noob questions.
ROBERT PETRICKHow is signal logic programmed into the DC system? Obviously, I need to study up on how relays function, but for now I'm just looking for the short answer.
Doughless ATLANTIC CENTRAL DC throttles see direction as east and west, not as forward and reverse. The best plan would still be to stop the train in the loop, throw the turnout, change the throttle direction and proceed. Which, if the loop contains multiple tracks for staging, is suddenly not as much of a big deal. ATLANTIC CENTRAL Side bar - one well designed DC system that has been in continous use since about 1965 exists on the Severna Park Model Railroad Club. The layout is a bit of a spaghetti bowl, but you don't really know that as you view it as a visitor. The layout is only about 12 x 35. Schematicly it is a loop to loop, and yes operators must throw reversing switches while they are inside the two "reversing blocks" Being respectful of the Severna Club and their needs, I have never understood the idea of having reversing loops on a layout. I'm mainly referring to published trackplans. Even when I was 14 and the major publications like 101 Trackplans had reversing loops as part of the mainline running, I was always drawn to the few trackplans that were more of an around the room design. When you mention having staging in the loop, yes, that is a great example of where reversing loops are needed. Also, passenger terminals, where railroads want to keep the passeger cars in the same order behind the locomotive...the whole train runs back and forth hundreds/thousands of miles. In both cases with staging and the passnger terminal, the train is going to be stopping. And an empty passenger train that's being turned is going to be traveling slow through that area anyway. Reversing loops on a 40 mph (or more) mainline? Respecting others that enjoy it, its not something I was ever drawn to. As you've said, trackplanning is a big part of the DC issue.
ATLANTIC CENTRAL DC throttles see direction as east and west, not as forward and reverse. The best plan would still be to stop the train in the loop, throw the turnout, change the throttle direction and proceed. Which, if the loop contains multiple tracks for staging, is suddenly not as much of a big deal.
ATLANTIC CENTRAL Side bar - one well designed DC system that has been in continous use since about 1965 exists on the Severna Park Model Railroad Club. The layout is a bit of a spaghetti bowl, but you don't really know that as you view it as a visitor. The layout is only about 12 x 35. Schematicly it is a loop to loop, and yes operators must throw reversing switches while they are inside the two "reversing blocks"
Being respectful of the Severna Club and their needs, I have never understood the idea of having reversing loops on a layout. I'm mainly referring to published trackplans. Even when I was 14 and the major publications like 101 Trackplans had reversing loops as part of the mainline running, I was always drawn to the few trackplans that were more of an around the room design.
When you mention having staging in the loop, yes, that is a great example of where reversing loops are needed. Also, passenger terminals, where railroads want to keep the passeger cars in the same order behind the locomotive...the whole train runs back and forth hundreds/thousands of miles.
In both cases with staging and the passnger terminal, the train is going to be stopping. And an empty passenger train that's being turned is going to be traveling slow through that area anyway.
Reversing loops on a 40 mph (or more) mainline? Respecting others that enjoy it, its not something I was ever drawn to.
As you've said, trackplanning is a big part of the DC issue.
Completely agreed, that is why my layout has no reverse loops in the mainline.
I will respond to others comments a bit later, have some business to take care of.
gregc ROBERT PETRICK An interlock and signaling system that would 1) prevent trains from entering a block that is occupied by another train, the following diagram from Classic Railway Signal Tower : New Haven Railroad S. S. 44/Berk shows that derails were used to at least slow a train that passed thru a STOP signal
ROBERT PETRICK An interlock and signaling system that would 1) prevent trains from entering a block that is occupied by another train,
the following diagram from Classic Railway Signal Tower : New Haven Railroad S. S. 44/Berk shows that derails were used to at least slow a train that passed thru a STOP signal
ATLANTIC CENTRAL SeeYou190 Doughless I would say that if your group of friends all have layouts that can support 5 to 6 operators, they are not typical home layouts. But that's a matter of experience and social circles. When I was in College in Nashville, there were about a dozen layouts I knew of that could host six or more operators. That became my goal. Back in Florida most layouts could really only handle three or four. Now, I know of none (other than two club layouts) that can handle more than three. Times change. If I built a layout that needed six operators, I seriously doubt I could ever get that many. -Kevin Really? The Round Robin group I was in has 12-15 people at someones house every week, and a total roster of participants numbering over 20. And that is just one group that covers about a 10 mile radius. A few calls and I could have a dozen operators on a weeks notice around here. Come October, this organization will have a full schedule of open houses in the Baltimore/Philli/Willmington area every weekend in November and December. Typically 5-8 layouts every weekend, generally grouped so you can easily see them all. https://www.modelrailroadopenhouse.com/index.html There are club layouts, museum displays, roundrobins and modular groups all over this region. And contrary to the experiance of others, lots of basement filling home layouts. Sheldon
SeeYou190 Doughless I would say that if your group of friends all have layouts that can support 5 to 6 operators, they are not typical home layouts. But that's a matter of experience and social circles. When I was in College in Nashville, there were about a dozen layouts I knew of that could host six or more operators. That became my goal. Back in Florida most layouts could really only handle three or four. Now, I know of none (other than two club layouts) that can handle more than three. Times change. If I built a layout that needed six operators, I seriously doubt I could ever get that many. -Kevin
Doughless I would say that if your group of friends all have layouts that can support 5 to 6 operators, they are not typical home layouts. But that's a matter of experience and social circles.
When I was in College in Nashville, there were about a dozen layouts I knew of that could host six or more operators. That became my goal.
Back in Florida most layouts could really only handle three or four.
Now, I know of none (other than two club layouts) that can handle more than three.
Times change. If I built a layout that needed six operators, I seriously doubt I could ever get that many.
-Kevin
Really? The Round Robin group I was in has 12-15 people at someones house every week, and a total roster of participants numbering over 20.
And that is just one group that covers about a 10 mile radius.
A few calls and I could have a dozen operators on a weeks notice around here.
Come October, this organization will have a full schedule of open houses in the Baltimore/Philli/Willmington area every weekend in November and December. Typically 5-8 layouts every weekend, generally grouped so you can easily see them all.
https://www.modelrailroadopenhouse.com/index.html
There are club layouts, museum displays, roundrobins and modular groups all over this region.
And contrary to the experiance of others, lots of basement filling home layouts.
As I said, social circles are going to sway a perspective. I'm thinking along the lines of space commitments, lifestyle choices, families, etc.
I would simply say that for every person who can have/want their basements full of trains, or even half of their basements full of trains, there are probably more people that have layouts that consume less space. I would assume those two model railroading goals conflict with each other, so the people don't visit each others' layouts much and wouldn't know how many other modelers are out there.
My personal definition of typical home layout is coming from speculation, not really personal experience.
But this topic is a sidebar to the thread.
- Douglas
ATLANTIC CENTRALDC throttles see direction as east and west, not as forward and reverse. The best plan would still be to stop the train in the loop, throw the turnout, change the throttle direction and proceed. Which, if the loop contains multiple tracks for staging, is suddenly not as much of a big deal.
ATLANTIC CENTRALSide bar - one well designed DC system that has been in continous use since about 1965 exists on the Severna Park Model Railroad Club. The layout is a bit of a spaghetti bowl, but you don't really know that as you view it as a visitor. The layout is only about 12 x 35. Schematicly it is a loop to loop, and yes operators must throw reversing switches while they are inside the two "reversing blocks"
ROBERT PETRICKAn interlock and signaling system that would 1) prevent trains from entering a block that is occupied by another train,
of course a signal can only warn an operator to stop. What would it take to prevent a train from entering an occupied block?
ROBERT PETRICK ATLANTIC CENTRAL The teardrop loop long enough to handle a the longest full train is much better than the toy like cut thru tracks. But there is no way to fully automate it like DCC. DC throttles see direction as east and west, not as forward and reverse. The best plan would still be to stop the train in the loop, throw the turnout, change the throttle direction and proceed. Which, if the loop contains multiple tracks for staging, is suddenly not as much of a big deal. That is not very different than DCC. On a loop like that, you exit the loop through the other leg of the turnout you entered from, and you have to throw the switch sometime between when the caboose clears the entry and the lead engine reaches the end. The thing is that you can throw the switch while the train is moving. Not a big deal.
ATLANTIC CENTRAL The teardrop loop long enough to handle a the longest full train is much better than the toy like cut thru tracks. But there is no way to fully automate it like DCC. DC throttles see direction as east and west, not as forward and reverse. The best plan would still be to stop the train in the loop, throw the turnout, change the throttle direction and proceed. Which, if the loop contains multiple tracks for staging, is suddenly not as much of a big deal.
The teardrop loop long enough to handle a the longest full train is much better than the toy like cut thru tracks. But there is no way to fully automate it like DCC.
DC throttles see direction as east and west, not as forward and reverse. The best plan would still be to stop the train in the loop, throw the turnout, change the throttle direction and proceed. Which, if the loop contains multiple tracks for staging, is suddenly not as much of a big deal.
That is not very different than DCC. On a loop like that, you exit the loop through the other leg of the turnout you entered from, and you have to throw the switch sometime between when the caboose clears the entry and the lead engine reaches the end. The thing is that you can throw the switch while the train is moving. Not a big deal.
So the DC layout I descibed earlier, you can keep the train moving while you throw the turnout. But you have separate reverse switches for the loop and the mainline.
You must be sure the loop reverse switch is set correctly for the train to enter (depending on which direction you are entering, clockwise or counter clockwise). Then, while the train is in the reverse loop block, you must throw the turnout and manually reverse the polarity of the mainline.
People have tried automatic schemes for this over the years, but they present other problems.
And they would present even more problems with wireless throttles like the Aristo.
In my view, the way I do it is a small compromise to maintain the east/west relationship of the buttons on the throttle, and streamline operation, especially considering I'm not fond of reverse loops in any case.
Related topic - how the wye works - if you are traveling west bound on my layout, and you want to pull your train into the staging yard on the tail of the wye, you align the route and simply pull in to the staging track you have selected.
Same is true if you appproach the wye from the east bound side.
The turnout positions and the power routing relays automaticly give you the correct polarity going in.
To leave the wye, the same is true. You align the route, lets say you want to come out of the staging yard and travel west bound on the mainline. You set your throttle direction to west bound and your train will move out of the yard and thru the wye heading west bound.
It does not matter if the trains was pulled in or backed in, all that matters is the route selected and the correct mainline direction selected on the throttle.
So if I was headed west, and wanted to turn the whole train on the wye, I would set a route into the wye and into an open staging track, drive the train in. Select the other route out of the wye, but NOT change my throttle direction because while the train will now be backing up, it will still be moving west bound on the mainline. Once the train is backed onto the mainline, and the route restored to the mainline, I would reverse the throttle direction to east bound, and the train will move forward east bound.
The turntable in the engine terminal works in a similar way, as they always did before DCC.
Tracks leading on to the turntable are on the east side, so you travel west to get on the turntable and west to get into the roundhouse. You travel east to get out of the roundhouse and to get off the turntable. Makes no difference which way the loco is facing.
The bridge rails are powered by the pit rail which is split in two. When the turntable spins around 180 degrees, the polarity of the bridge has been swapped.
ROBERT PETRICK ATLANTIC CENTRAL This layout is really a candidate for DCC. Because, unless it is REALLY stretched out, 3 trains will be too close to each other. Typically in any good cab control scheme, a train needs to "own" a minimum of two blocks at a time. Three is sometimes better depending on the layout design Even though the sketch I included earlier looked kinda like a 4x8, it was generic and schematic in nature and could be stretched or distorted at will. Suppose the room was very large (say, 50' by 30') and there was plenty of room for trains to stretch out and occupy several blocks and there was room for the operators to be "inside the loop" and maintain your east-west face front operating style. And suppose it was really a point-to-point scheme with either a wye on each/either end or a teardrop loop on each/either end. In other words, some way to turn trains at the terminals. Such as . . . Off site - as in outside the building? or as in the next room over? I'm not a fan of either, my dispatcher will have a view of much of the layout. But his panel will show him, and allow him to control - cab assignments, block occupancy, permission to proceed, and turnout position. All done with little lighted pushbuttons on or near the track diagram. There is no provision for remote operation - but one could be built. Offsite as in the next room or in some quiet corner of the main layout room. The dispatcher's attention is on the control board and not on the layout, and all communication is done through the phones and not across the room ear-to-ear. Reverse loops - as shown on your diagram, those reverse loops violate several of my layout design "rules": Left is always west, right is always east. This is so much easier for operators to understand and reinforces the idea of "going somewhere". The layout is viewed from "inside" the "loop". Point to point operation is created by stopping in the hidden continious staging. So on my layout, every viewer position is standing on the "south" side of the tracks looking north. I have a dead end wye for staging, it is semi-automatic with regard to reversing. But because you are "changing direction" you must bring you train to a stop and reverse the direction of your throttle. It is after all a wye, not a loop. Yes, I understand. But what about a teardrop or other "loop" that is long enough to contain the longest train on the layout and with broad enough radius to comfortably accomodate the longest steam engine? Say, 6 or 8 feet in diameter. What would you need? Roughly one relay per turnout, cab selection relay board for each block which for three throttles will require three relays each if 5 amps is considered adequate. Some sort of driver for each signal head - can be solid state, relay, or polarity based diode logic. Detectors - preferably inductive and not connected to the power circuit, and preferably with descrete relay outputs. LED lighted pushbuttons. A box or two of CAT5 cable. Just by coincidence, I got a brand-new unopened 1000-foot box of CAT 5 cable from the office when we switched over to CAT 6. I stripped out the twisted pairs as needed for my DCC signaling and fascia mounted turnout control push buttons. Are the 26 AWG wires heavy enough for your scheme? Or, is another stash of heavier gauge wire needed to be on hand? Keep in mind I'm only asking generic questions about some as-yet unknown generic layout to get a feel for general features of a DC command and control system. Thanks. Robert
ATLANTIC CENTRAL This layout is really a candidate for DCC. Because, unless it is REALLY stretched out, 3 trains will be too close to each other. Typically in any good cab control scheme, a train needs to "own" a minimum of two blocks at a time. Three is sometimes better depending on the layout design
Because, unless it is REALLY stretched out, 3 trains will be too close to each other. Typically in any good cab control scheme, a train needs to "own" a minimum of two blocks at a time. Three is sometimes better depending on the layout design
Even though the sketch I included earlier looked kinda like a 4x8, it was generic and schematic in nature and could be stretched or distorted at will. Suppose the room was very large (say, 50' by 30') and there was plenty of room for trains to stretch out and occupy several blocks and there was room for the operators to be "inside the loop" and maintain your east-west face front operating style. And suppose it was really a point-to-point scheme with either a wye on each/either end or a teardrop loop on each/either end. In other words, some way to turn trains at the terminals. Such as . . .
Off site - as in outside the building? or as in the next room over? I'm not a fan of either, my dispatcher will have a view of much of the layout. But his panel will show him, and allow him to control - cab assignments, block occupancy, permission to proceed, and turnout position. All done with little lighted pushbuttons on or near the track diagram. There is no provision for remote operation - but one could be built.
Offsite as in the next room or in some quiet corner of the main layout room. The dispatcher's attention is on the control board and not on the layout, and all communication is done through the phones and not across the room ear-to-ear.
Reverse loops - as shown on your diagram, those reverse loops violate several of my layout design "rules": Left is always west, right is always east. This is so much easier for operators to understand and reinforces the idea of "going somewhere". The layout is viewed from "inside" the "loop". Point to point operation is created by stopping in the hidden continious staging. So on my layout, every viewer position is standing on the "south" side of the tracks looking north. I have a dead end wye for staging, it is semi-automatic with regard to reversing. But because you are "changing direction" you must bring you train to a stop and reverse the direction of your throttle. It is after all a wye, not a loop.
Reverse loops - as shown on your diagram, those reverse loops violate several of my layout design "rules":
Left is always west, right is always east. This is so much easier for operators to understand and reinforces the idea of "going somewhere".
The layout is viewed from "inside" the "loop".
Point to point operation is created by stopping in the hidden continious staging.
So on my layout, every viewer position is standing on the "south" side of the tracks looking north.
I have a dead end wye for staging, it is semi-automatic with regard to reversing. But because you are "changing direction" you must bring you train to a stop and reverse the direction of your throttle. It is after all a wye, not a loop.
Yes, I understand. But what about a teardrop or other "loop" that is long enough to contain the longest train on the layout and with broad enough radius to comfortably accomodate the longest steam engine? Say, 6 or 8 feet in diameter.
What would you need? Roughly one relay per turnout, cab selection relay board for each block which for three throttles will require three relays each if 5 amps is considered adequate. Some sort of driver for each signal head - can be solid state, relay, or polarity based diode logic. Detectors - preferably inductive and not connected to the power circuit, and preferably with descrete relay outputs. LED lighted pushbuttons. A box or two of CAT5 cable.
What would you need?
Roughly one relay per turnout, cab selection relay board for each block which for three throttles will require three relays each if 5 amps is considered adequate.
Some sort of driver for each signal head - can be solid state, relay, or polarity based diode logic.
Detectors - preferably inductive and not connected to the power circuit, and preferably with descrete relay outputs.
LED lighted pushbuttons.
A box or two of CAT5 cable.
Just by coincidence, I got a brand-new unopened 1000-foot box of CAT 5 cable from the office when we switched over to CAT 6. I stripped out the twisted pairs as needed for my DCC signaling and fascia mounted turnout control push buttons. Are the 26 AWG wires heavy enough for your scheme? Or, is another stash of heavier gauge wire needed to be on hand?
Keep in mind I'm only asking generic questions about some as-yet unknown generic layout to get a feel for general features of a DC command and control system.
Thanks.
Robert
OK, much more practical layout.
Side bar - one well designed DC system that has been in continous use since about 1965 exists on the Severna Park Model Railroad Club. The layout is a bit of a spaghetti bowl, but you don't really know that as you view it as a visitor. The layout is only about 12 x 35. Schematicly it is a loop to loop, and yes operators must throw reversing switches while they are inside the two "reversing blocks" .
But the cab control portion of that system is interesting. Three mainline operators, all sitting next to each other near the middle of the layout, each has a control panel that maps the whole mainline.
Each block has an 1/8" phone jack in the diagram. Your throttle is connected to a block by plugging a phone plug which is shorted out internally so it acts like a switch.
You are only allowed two phone plugs. You must watch the detection board overhead and not plug into an occupied block.
Each panel has separate reverse switches for the mainline and the two reversing blocks.
A dispatcher operates all mainline turnouts from a separate panel, but the two critical turnouts for the loops can also be operated at the cab panels.
Yes, its old school, yes you have to constantly manage the reverse loops and mainline polarity. But what you don't have to do is turn off the blocks you leave. That happens when you pull the plug and advance it to the next block.
Pretty clever in 1965, and suitable for a layout of that size.
It also has a full working signal system.
Back to your track plan.
Small control panels would be located at each turnout/control point. They would have turnout controls and cab assignment buttons for each block that connectsd to the control point. Blocks can run from control point to control point, or there can be more than one block between control points. This depends on several operational factors but in most cases there would be no more than two blocks between control points.
The reasoning for that will be more clear as you understand the "progressive" nature of the cab assignment process - be it by the dispatcher or the engineer.
So this version of the layout would work fine, and require the same list of materials depending on the exact number of blocks and turnouts.
The stop and proceed at the loop would be the only "concession" to DC control without introducing the manual operation of reversing switches.
ROBERT PETRICK Track fiddler K. If only one knew how to do it? TF Okay. Forget my previous rambling post for a moment. Let's take another approach. Here's a sketch of a typical (fairly) simple layout: Keep in mind this is only a generic schematic diagram, and it can be stretched or distorted to fill an entire basement. How would such a thing be wired for DC and what components would be necessary to meet the following criteria: 3 handheld wireless throttles controlling 3 separate trains simultaneously and independently. An interlock and signaling system that would 1) prevent trains from entering a block that is occupied by another train, and/or 2) set signal indications that show occupation, but would allow trains to illegally run a red signal and enter an occupied block. Allow signal and routes to be controlled by an offsite dispatcher. Allow trains to run catch-as-catch-can by engineers simply following the signal indications that are set automatically using block detection systems. Allow trains to smoothly transition between blocks at speed (especially the reversing section blocks) without having to flip toggle switches or lay down one throttle and pick up another. I hope my simplistic approach and silly-ass comments don't upset or insult anyone. Robert
Track fiddler K. If only one knew how to do it? TF
K.
If only one knew how to do it?
TF
Okay. Forget my previous rambling post for a moment. Let's take another approach.
Here's a sketch of a typical (fairly) simple layout:
Keep in mind this is only a generic schematic diagram, and it can be stretched or distorted to fill an entire basement.
How would such a thing be wired for DC and what components would be necessary to meet the following criteria:
I hope my simplistic approach and silly-ass comments don't upset or insult anyone.
This layout is really a candidate for DCC.
Your wish list:
This might be a good place to explain the Aristo throttle. It uses all buttons, direction is controlled by a "left " button and a "right" button. Guess which way your train always goes?
Not the best photo.
Many DC layouts that I have seen over the years have delt with reverse loops by requiring trains to stop and change the direction of their throttle, not by the traditional method of reversing the mainline polarity.
My only other reversing loop is a hidden staging tool on the WESTERN MARYLAND branch line. Again, trains stop, turnouts thrown, throttle direction is changed to the new direction of movement, train proceeds.
More info later,
Robert,
Yes, about 1700 vinyl records, many near mint (but they do get played), many original radio station promo copies, and some that simply date to 1971 or so when I got interested in popular music.
I also design and build HiFi speakers, just another reason I can't deal with onboad sound. After you listen to good speakers long enough, anything less sounds like that nine transistor radio I had in 1968. That had a 1" speaker as well.....
I had a Victrola, a rare one only made for about 10 months, 1929?, I have the info somewhere. But we sold it when we sold the big 1901 Queen Anne house, realizing I already had too many hobbies.
So, I have considered finishing or better organizing the info on the control system. Which might actually be easier as I document it for the new layout.
First let me try to explain a few things, earlier in this thread is a narrative of how the system "operates" from the persepective of the engineer and /or dispatcher. If you can find that, in serveral of my replies to Greg, that might be a good starting point to understand the system.
Key important point, turnouts and cab assignments are done with lighted pushbuttons on track diagram control panels and this controls can, and are, repeated at multiple locations.
So a turnout can be thrown at a local tower panel, OR, at the dispatchers panel.
Cab assignments can be made at multiple tower panels or at the dispatchers panel.
I would be happy to share the technical info with you. Some of it is digital, some is not. Only a few of the drawings have been scanned.
I strongly recommend finding the discription I did for Greg, or I will find it and repost it. Understanding the operation, and the user interface, is important to understanding the tech.
The tech is the application of some very common machine tool and motor starter circuits which are litterally 100 years old.
I will send along a few things to you directly. Aswell as follow up here for those interested.
I will address your other post with the track plan separately.
K. Kindly
I'm drowning here, and you ain't even describing the water?
dehusman Can't tell you the specifics, but would take many times the wiring as a DCC layout.
Can't tell you the specifics, but would take many times the wiring as a DCC layout.
Yes, I understand.
For example #1. With DCC you buy a radio throttle DCC system, two additonal radio throttles, and two auto reversers. You isolate the two reversing sections, connect the them to the auto reversers, then connect that to the main power. Connect the main power to the track. Probably should have a few feeders scattered around the layout for good connectivity. Plug in the system and change the addresses on the throttles to be different from each other if required. You should be up and running in an afternoon.
With DC you would have to isolate the railroad into seprate blocks. Then build a panel or series of panels that would allow the throttles to be connected to individual blocks. Buy a radio DC system (don't know if that would entail buying three single systems or one system and additonal throttles.) Controling the reversing section would entail installing DPDT switches to control the reversing track polarity or if you wanted "automatic" reversing, you would need contacts connected to the switches or some sort of "gate" that when triggered makes a relay change the polarity of the track. You could have it up an running in a couple days.
Yes, I understand. To have a working (semi-prototypical) signal system in DCC, you'd also need to break up the layout into individual blocks (I count roughly about 15 or so in the above sketch) and have printed circuit boards to monitor and detect occupancy and other printed circuit boards to set the color indication on the signal masts. Digitrax makes such things for a (fairly) reasonable price. That's why I (as a novice) could install signals on my layout. There were packaged plug-and-play stuff available. Similar, easily installed products for smooth and reliable transition through reversing sections were also readily available.
ROBERT PETRICKHow would such a thing be wired for DC and what components would be necessary to meet the following criteria:
Dave H. Painted side goes up. My website : wnbranch.com
Not at all Robert.
Again, if only one knew how to do it?
ROBERT PETRICKyou said you have charts, and diagrams, and (the beginnings of) a narrative. It could make an interesting article for publication in some railroad hobby related publication. Or it could be a massive waste of time. Need any help?
It could make an interesting article for publication in some railroad hobby related publication. Or it could be a massive waste of time. Need any help?
while i think it wouldn't be that interesting to see a detailed description of "how" the nodes work with relays, i'm am interested in better understanding of what the nodes do, what the connections are to other nodes and now that i've heard about it, the CTC panel?
i've seen centralized control systems in PCs, i'd like to better understand a distributed approach
It was stated from the very beginning that off-topic and tangential posts are not only allowed, but encouraged. Well . . . let’s see how far that idea goes before people start scratching their heads and rolling their eyes at me. Even though this might seem to be off-topic, it gets at the heart of my thoughts about his thread.
This is a beautiful piece of Excellence in N scale detail except for rivets. My brother gave it to me for my Birthday.
It's one of those Athearn hybrid DC/DCC with sound, and knows what track it's running on.
It's creeping function Sucks. The sound is tinny and not enjoyable.
I'm used to listening to good sound from a Carver sound processor connected to a Denon or Onkyo amplifier.
Bruce at Scale Model Supply said if you go into the locomotive and disconnect the sound function, it'll creep off the line beautifully.
That would be much more important to me if only one knew how to do it.
I'm sorry for your less-than-stellar experience with NCE, John. I've only replaced the keypad on my now 17-year old Power Cab and just sent it into NCE to replace the RG12 connector. Very happy with their product.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
As I said above, we tried going virtually all dcc, and have had a number of issues. (We have a simple dpdt toggle switch to toggle the power supply from the wall to dc to dcc as needed). For quite some time, well over a year if not two, we had only one plain dc loco remaining, an MTH FEC SD70M-2 that my son likes and didn't want to part with.
All the rest of the locos had/have dcc (until a few weeks ago when I started replacing mine with plain dc locos).
We have the NCE Power Cab, and not the Pro Cab. It is maybe 3 or 4 years old, tops. Now the speed dial on that Power Cab is just starting to fail. One may turn the wheel one direction just a couple steps, and the result may be the exact opposite--instead of accelerating, it may decelerate. Or instead of slowing down a couple steps it may surge.
In general I'm just really not impressed with NCE. In a lifetime of using MRC dc power supplies, 50 years now, they were all relatively durable.