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Subject: 
Re: Even more Wow!! for your buck!!! was Re: Woo Hoo!!!!! (part deux...)
Newsgroups: 
lugnet.org.ca.rtltoronto, lugnet.trains
Date: 
Tue, 3 Jun 2003 02:23:44 GMT
Viewed: 
1256 times
  
In lugnet.org.ca.rtltoronto, Larry Pieniazek wrote:
In lugnet.org.ca.rtltoronto, Brian H. Nielsen wrote:
In lugnet.org.ca.rtltoronto, Larry Pieniazek wrote:
In lugnet.org.ca.rtltoronto, Brian H. Nielsen wrote:
In lugnet.org.ca.rtltoronto, Larry Pieniazek wrote:
In lugnet.org.ca.rtltoronto, David Koudys wrote:

<snip>

Regarding reverse loops and DCC I seem to recall that it's possible to
automate them so you don't have to cut gaps that the motor has to coast
across

See this track diagram

http://members.shaw.ca/sask.rail/dcc/loop.html

   I'm not up on DCC, but with normal track it is normally done by having the
loop divided into 2 power blocks,

That diagram is divided into two blocks. One for the approaches, and one for the
reverse loop itself. That's standard wiring, been done that way since I was a
wee lad, there's no need to divide the reverse loop itself into two blocks.

With conventional control  (for example the old ATLAS line of components) you
reverse the loop block to match which way the train enters and while the train
is in the block, you reverse the approach block.

   Okay, yeah, my memory of what I too used to do years ago got cross-wired.

   Then I guess I don't understand the set-up that is causing his need for a gap
to be crossed.  Is it a DCC related issue or simply him not reversing the
polarity of the approaches while in the loop?


The latter I think... by having a truck long gap, the motor coasts across the
gap but never shorts out from one wheel set to the other, once it hits the
powered side again (even though the polarity is reversed) it just continues on.

This is actually an elegant solution if you can handle having the trains lurch a
bit. At the speeds we work at that's not a problem. For a two truck diesel in HO
that has interconnected power pickups on the trucks, and which is operating at
realistic speeds, it might not work well at all.

Brian H. Nielsen

Yep--Larry hit it on the head--the isolated section is so there isn't one set of
wheels on one polarity, and the other set of wheels on the reverse polarity--

(see if this font is really courier ;) )


######################

Track



    TTTTT
    O   O
#######################

Track with electric truck on it



    TTTTT
    O   O
###### #################
Pol.AB  Pol.BA

Track with small gap--two different track sections opposite polarity--wheels on
either side causes short


       TTTTT
       O   O
###### ##### ###############
Pol.AB  none   Pol.BA

Truck crosses gap--no shorts, no electricity at all

If the engine is going fast enuf, as Larry mentioned, it'll cross the gap no
problem.


Though the other idea, as Larry pointed out earlier, which is to switch the
polarity whilst the truck is entirely on that section is a great one, it adds a
further complexity--i.e. switches and knowing when the truck is in that 'block'.

THe solution above runs without any tipe of intervention at hte cost of the
motor not getting any electricirty whilst on the insulated gap--for LEGO doesn't
seem to be much concern.

After testing for an hour this evening on the layout in my living room, I have
noticed that, unless you're moving exceedingly slow, there is no problem with
the insulated gap.  What is a big headache, however, are the switches--the train
invariably ends up losing comunication across the switches at any speed.
Doesn't happen all the time, but half the time the engine just shudders thru the
switch--and only on the turn--the straight thru seems to be less of a problem.
I have wired it up such that both sides are 'live' at all times, no matter where
the switch is, but still the train shudders thru half the time.

Anyway, more playing :)

I'll let you know how it goes.

Dave K



Message has 2 Replies:
  Re: Even more Wow!! for your buck!!! was Re: Woo Hoo!!!!! (part deux...)
 
In lugnet.org.ca.rtltoronto, David Koudys wrote: <snip> (...) And here's 'more playing...' (URL) two pics, but fun ones... One of these pics shows how old my ccd in my digital camera is--all the 'blank' pixels. Eh, it still works and is now on (...) (21 years ago, 3-Jun-03, to lugnet.org.ca.rtltoronto, lugnet.trains)
  Re: Even more Wow!! for your buck!!! was Re: Woo Hoo!!!!! (part deux...)
 
(...) An easy solution to this is to have two locomotives in the train, each tuned to the same DCC channel. If one loco loses communication, the other will push it through the bad spots... That probably why real trains have two locos, right? :) (...) (21 years ago, 3-Jun-03, to lugnet.org.ca.rtltoronto, lugnet.trains)

Message is in Reply To:
  Re: Even more Wow!! for your buck!!! was Re: Woo Hoo!!!!! (part deux...)
 
(...) The latter I think... by having a truck long gap, the motor coasts across the gap but never shorts out from one wheel set to the other, once it hits the powered side again (even though the polarity is reversed) it just continues on. This is (...) (21 years ago, 3-Jun-03, to lugnet.org.ca.rtltoronto, lugnet.trains)

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