Fascinating But Boring Book

[rrinker]

To be fair, you are comparing people from different generations. Most of Westcott’s ideas, for example, were published before or while Bruce Chubb was just experimenting operations with Lionel trains, long before CMRI or the parts that made it possible were available.

And Westcott went way beyond cab control schemes - he came up with the Twin-T detector, and various TAT throttles. Not bad for a guy educated in the days of relays and vacuum tubes. ANd of course he did a lot more than just electrical stuff.

Too many these days seem to think the only solution is the one using the latest and greatest components. Good engineering is using the most appropriate component for the task at hand, not just the latest thing. Sometimes a relay just does a better job - solid state relays are not just drop in replacements for all uses.

–Randy

[gregc]

Good engineering is using the most appropriate component for the task at hand, not just the latest thing.

processors are good for logic and in some cases still rely on (latching) relays for controlling higher current devices. it’s good to have more than one tool in the toolbox.

So why do you need a computer or micro processor to do what one 4PDT relay per block detector and turnout can do? Less wire? Not really.

because a single processor can often replace more than one relay and often serve multiple purposes (e.g. signal control, communication node, servo controller, …) at the same time, and can significantly reduce wiring and maintenance

[ATLANTIC_CENTRAL]

rrinker
Good engineering is using the most appropriate component for the task at hand, not just the latest thing.

processors are good for logic and in some cases still rely on (latching) relays for controlling higher current devices. it’s good to have more than one tool in the toolbox.

ATLANTIC CENTRAL
So why do you need a computer or micro processor to do what one 4PDT relay per block detector and turnout can do? Less wire? Not really.

because a single processor can often replace more than one relay and often serve multiple purposes (e.g. signal control, communication node, servo controller, …) at the same time, and can significantly reduce wiring and maintenance

Greg,

In the early 1980’s I was wiring and programing some of the first Programable Logic Controllers being used to replace relays in industrial applications.

I was responsable for one of the very first of such applications of PLC’s to run a waste water pumping station here in Baltimore.

I get it.

But that’s just it, in my application I don’t need all that. But I do need high current handling and discrete switching.

I use Dallee inductive dectectors which have a DPDT relay output.

It then only takes one 4PDT relay per turnout (averaged out over the whole system) to provide all the signal logic and power routing logic for the whole system.

My dollar cost average to aquire the sealed ice cube relays is less than

[gregc]

So why do you need a computer or micro processor to do what one 4PDT relay per block detector and turnout can do? Less wire? Not really.

Simply select the desired route, and assign the primary blocks on either side to your throttle and the power is automaticly routed thru. The same relays do this as well. They too need to be able to handle the 5 amps. So where is all this savings in wire?

it’s a bit more than just block detection and turnouts. since you’re DC, you need the 5A relays to control power to the track, and since you’re familiar with relay logic, you’re comfortable using the same relays for block detection and turnouts.

the context of the problem can make one solution economical for one person but not another. I looked at high efficiency heating and concluded that it wasn’t economical for me when I replaced my system. What I realized is that in a new home, the high efficiency furnace saves the cost of a chimney.

in your case, relays do power routing. But I don’t think this is an issue if you’re using DCC (there’s no need for a chimney).

where wiring can be saved is using nodes as Bruce Chubb described. Nodes can provide provide I/O to nearby devices such as block detectors, turnouts and signals. Node can also connect to panel switches and lamps. All nodes can be connected on a single 4 wire (RS-422) bus. And a computer can connect to the node bus through it’s serial interface.

One node can monitor block detection on a long block while two separate nodes control signals at each end of the block. Even on medium layouts, the reduction in wire can be significant.

instead of having long lengths of wire stretched across the layout, connections are to the nearest node, and if one isn’t available, you can add

[ATLANTIC_CENTRAL]

Greg,

I completely agree, there are situations where software is the easier solution.

But just like the DC or DCC question, one size does not fit every situation.

As for the track diagram you posted, I would be interested to see a scale drawing of the track. It sems unlikely that it would desireable to have every possible complete route as a choice, but rather it should be broken down in to sections, which would simplify the logic, hardwired or software.

But I could be wrong about that.

On a typical interlocking on my layout, as stated, it only takes one or two relays per turnout to get the needed logic. You remember of discussion about the wye.

As a relay logic designer, I never use latching relays, they cost a lot more. Too easy to just seal a relay on with a contact. But I understand why you would need/want them with solid state logic.

AND, most important, many of the products being used today for software type solutions did not exist, or were not affordable, or readily available 15-20 years ago when I began developing my control system.

Which speaks to a simple fact, once people are invested in something that works, why change it just to change? If we started from scratch tomorrow, we could build something better than DCC, but it won’t happen, because DCC works just fine.

And, being a building design professional I would likely agree with your heating choice as well.

Sheldon

[dknelson]

Curious about the “how to burn your hose down” dig at Westcott’s book, I’ve never seen anything particualrly dangerous there - considering he is dealing with the low voltage trainc ontrol side of things. The book covers several differnet methods of cab control for DC operation, each has its own pros and cons in regards to simplicity and flexibility of control, but none of them seem to be designed to make it easy to set you layout on fire.

The earliest edition of Westcott’s wiring book spent more time and space on making your own power supplies from scratch, so there was more than a little 110 volt wiring in there that by today’s standards would, yeah, not be “UL approved,” including some of the troubleshooting suggestions.

While a little bit of that was left in the final edition by that time it had been re-written to reflect that almost all readers, even those with big layouts, would be buying commercial power supplies.

Dave Nelson

[SeeYou190]

The earliest edition of Westcott’s wiring book spent more time and space on making your own power supplies from scratch, so there was more than a little 110 volt wiring in there that by today’s standards would, yeah, not be “UL approved,” including some of the troubleshooting suggestions.

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My copy of Wescott’s book is from the early sixties. I think it is the third printing.

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It still contains information on different voltages and frequencies in different locations in the USA, even though I think by the 1960s we were standardized.

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The uninsulated AC connections and various speed controls are scary. Your house would be a concern, dogs and children were also in danger!

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Reading Model Railroader from 1946-1955 also includes all kinds of questionable wiring ideas.

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-Kevin

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[rrinker]

Back in the 70’s and early 80’s I built power supplies - Radio Shack was a ready source for the componets liek transformers, toggle switches, neon lights, fuse holders, bridge rectifiers…and metal project cases. Which I never grounded. I think I made 3 in total, a 6.3V one, a 12V one, and one using the 18V CT transformer to get a +/- 9V for op amp circuits.

Way back in the day, when copper oxide rectifiers were new (and horrible), many modelrs ran with car batteries. Most any article I can remember reading in goign through the archive (I have the DVD version, started at the very first issue and read them all in order) either had a fuse or, if missed by the author, the next month’s issue had a note that you had better use a fuse because car batteries can dump a lot of current into a short. ANd in those days - it took TWO car batteries, because they were all 6V. Yes, there were some crazy things - like in the first issue, the guy with the outdoor trolley layout using 110VAC in the overhead. Burn your house down? Not very likely. Give someone a shock? Well, if they were stupid and touched the wire. Obviously the guy had no little children runnign around, and no pets (the article does mention that there is no indication of the effect on the locl squirrel population - sort of indicating “Ed.” (probably Al Kalmbach himself) thought this was a rathe rsilly idea and no one should duplicate it. But that was also a time when you didn;t have to say “don’t try this at home” on everything even remotely dangerous because people weren’t that dumb. I don’t think anyone tried to drive their Model T between two trolley cars because the Keystone Kops could do it. As for bare connections - at the time a lot of homes would still have knob and tube wiring. e think that was insanely dangerous by todays standards - but was it? The two conductors were widely spaced, certainly not in a position where some overheating could melt insulation and cause a short. Or where a nai