Large Scale Central

Block Detection

Electronics
#1

Howdy folks
I thought Id add a new forum on electronics, since Im interested in using them to better my “train experience”.

That said, Im interested in adding signaling and block detection to my outdoor RR. I run battery/rc, and I dont have any intention of cleaning my rail, so typical current-drop detection wont work. I’ve contemplated using some sort of photo-optics, but Im not sure that will work unless I have detectors every couple of feet (How do you detect a single car in a block?).

So, Im looking for ideas, and/or pointers to circuits. My intention is to use CMRI boards with homegrown signals.

Anyone?

#2
Bob McCown said:
Howdy folks I thought Id add a new forum on electronics, since Im interested in using them to better my "train experience".

That said, Im interested in adding signaling and block detection to my outdoor RR. I run battery/rc, and I dont have any intention of cleaning my rail, so typical current-drop detection wont work. I’ve contemplated using some sort of photo-optics, but Im not sure that will work unless I have detectors every couple of feet (How do you detect a single car in a block?).

So, Im looking for ideas, and/or pointers to circuits. My intention is to use CMRI boards with homegrown signals.

Anyone?


How about magnets and reed switches? Together with a flip-flop latching circuit.

#3

Hmm… interesting idea. I think that might be the same issue as optical, but its worth a try. In smaller scales, where we have track power and resistance wheel sets, a single car (like a caboose left behind) will still show the block occupied. Id like to be able to implement that outdoors, but I may not be able to.

#4

Bob,

You could still use the standard CMRI Optimized Detectors together with resistors both on the engines and the cars. It would detect in the same manner as it detects single cars in any block.

On the magnet front, that would work if you count the cars when they enter the block and exit the block. Clear depends on the counts matching. Can’t have industries to drop off in the block unless you pick up the same number of cars.
But you can get around that by having magnets only on the engine and the last car, like a FRED. Cascade two flip-flops and you’re set; they act like a counter.

#5

But don’t the ODs still look for voltage drop across the rails? of course, I putting a resistor on all 4 wheelsets might do it, ONE of them may show up. And with surface mount resistors being so cheap, the cost-per-axle is literally a pennty or two.

Time for experiments.

#6

Can youse guys slow down for those of us who are electronically challenged? Or at least translate it into English?

#7

Bob: here is one option. Ignore the track power part, uses magnets. only uni-directional, is this what you want?

http://dcc-bitswitch.com/track_signal.htm

I have a simple option for auto routing a train through a switch also if you are interested.

#8

I was going about this all wrong. Since I have no track power, and my locos are all RC (no rail connections except antenna), I can just run a current across the rails. A test boxcar with metal axles, with jumpers on all 4 axles, show that it detects it even on dirty brass and/or alum rail.

Cool!

#9
Bob McCown said:
I was going about this all wrong. Since I have no track power, and my locos are all RC (no rail connections except antenna), I can just run a current across the rails. A test boxcar with metal axles, with jumpers on all 4 axles, show that it detects it even on dirty brass and/or alum rail.

Cool!


Hmmmm… Bob … I thought you got that!?! It’s just like the real railroad’s track circuit. That is the old stuff, the new stuff is a bit more complicated. :wink: :slight_smile:

#10

Bob:

If you’re using rolling stock with insulated wheels, you can get conductive paint to put a ‘stripe’ from wheel to wheel or from wheel to axle, thus bridging the insulator bushings. Usually easier than putting resistors or shorting wires across the insulators.

Happy RRing,

Jerry Bowers

#11

This Months Model Railroader has an article in Signals on it…I looked at it for notes on modeling an Engine Terminal…then found out it was a reprint of an article they ran several years ago…

#12

At Marty Cozad’s last week, we witnessed a simple but effective Optical/Audio Block Detection System that seemed to work quite well. Installation only took minutes.

“Stan, your train”

“STAN, your train”

“STAN, YOUR TRAIN!!!”

You’ll need to talk to Stan Cedarleaf for how it was installed, but everyone was able to use it with their equipment, immediately.

:wink:

#13

The complete scenario:

Ric Golding said:
(Locomotive derails approaching high bridge, but keeps going) "Stan, your train" (Cars follow suit) "STAN, your train" (Train moves onto bridge) "STAN, YOUR TRAIN!!!" (THUD!!!)(followed by more thuds) (Dreadful silence)(Man in black hat observed leaving scene)
#14
Chris Vernell said:
The complete scenario:
Ric Golding said:
(Locomotive derails approaching high bridge, but keeps going) "Stan, your train" (Cars follow suit) "STAN, your train" (Train moves onto bridge) "STAN, YOUR TRAIN!!!" (THUD!!!)(followed by more thuds) (Dreadful silence)(Man in black hat observed leaving scene)
Funny, funny, funny! I remember only one guy in a black hat from the pictures I've seen ... and yes he seems to be connected with those happenings. Or at least it appears that way when one reads certain posts.
#15

But there is this other fellow with a camera slung around his neck that’s also been known to cause his share of accidents.

The story as I heard it was that said person got his train running and took off elsewhere, TX and camera in hand and was nowhere to be found when said train went “THUD”.

#16

Stan Happens

#17
Ric Golding said:
Stan Happens
Not even an automatic block will fix that one. :lol:
#18
Chris Vernell said:
The complete scenario:
Ric Golding said:
(Locomotive derails approaching high bridge, but keeps going) "Stan, your train" (Cars follow suit) "STAN, your train" (Train moves onto bridge) "STAN, YOUR TRAIN!!!" (THUD!!!)(followed by more thuds) (Dreadful silence)(Man in black hat observed leaving scene)
LOL!!!
#19

Ignoring all that crap…

Further tests are promising. I have two separate test blocks set up, and they seem to detect just fine. Now to work on the rest of the design.

#20

Anyone know the effective range of a photo transistor/irLED pair? Would I be able to use it over a span of say 10" to detect a 1:20 train in between?