My son runs a DCC system using Hornby's Select unit.  He has three
ovals of track on an 8' x 4' surface.  He's been having reliability
problems so I have removed the inner oval to reduce the overall size
of the track run.

Is there a 'rule of thumb',  guideline or rule that dictates the
maximum run of track for a given size of controller ?

Chris

Dragon Heart wrote:
> 
> My son runs a DCC system using Hornby's Select unit.  He has three
> ovals of track on an 8' x 4' surface.  He's been having reliability
> problems so I have removed the inner oval to reduce the overall size
> of the track run.
> 
> Is there a 'rule of thumb',  guideline or rule that dictates the
> maximum run of track for a given size of controller ?
> 
> Chris


NO!

The length of track is irrelevant to the amperage of power supply.
What does matter is the way the electricity gets to the locomotive.
Rail joiners are definitely imperfect electrical connectors, so you need
feed rails at regular intervals.
The further the feeder track from the power supply the thicker the wire
connections need to be.
A given wire has a specific resistance per foot/metre so a long feed
wire will lose voltage - the train runs slower.
A second feed section on an oval will effectively halve the resistance
between power supply and loco because the electricity then has two
paths, both of which get utilzed in inverse proportion to their
resistance.
I take this system to it's logical conclusion and fit a feed wire to
every length of rail - trains run at constant speed anywhere on the
layout.

Regards,
Greg.P.

In message 
          Greg Procter  wrote:

> Dragon Heart wrote:
> > 
> > My son runs a DCC system using Hornby's Select unit.  He has three
> > ovals of track on an 8' x 4' surface.  He's been having reliability
> > problems so I have removed the inner oval to reduce the overall size
> > of the track run.
> > 
> > Is there a 'rule of thumb',  guideline or rule that dictates the
> > maximum run of track for a given size of controller ?
> > 
> > Chris
> 
> 
> NO!
> 
> The length of track is irrelevant to the amperage of power supply.
> What does matter is the way the electricity gets to the locomotive.
> Rail joiners are definitely imperfect electrical connectors, so you need
> feed rails at regular intervals.
> The further the feeder track from the power supply the thicker the wire
> connections need to be.
> A given wire has a specific resistance per foot/metre so a long feed
> wire will lose voltage - the train runs slower.
> A second feed section on an oval will effectively halve the resistance
> between power supply and loco because the electricity then has two
> paths, both of which get utilzed in inverse proportion to their
> resistance.
> I take this system to it's logical conclusion and fit a feed wire to
> every length of rail - trains run at constant speed anywhere on the
> layout.
> 
> Regards,
> Greg.P.

It's been a looong time since (40 years..) I used set track, but on 
my Mk.1 cellar layout (Hornby Super 4!!) mixed with Peco (about 20' x
16) I just used to nip joiners up with a pair of pliers when laying 
the track to get a good interference fit. This removed all problems 
permenantly and needed only one feed from each controller - it took 
a coupe of attempts sometimes but was much easier that extra wiring.

Just my 2p.

Cheers
Richard

-- 
www.beamends-lrspares.co.uk       sales@beamends-lrspares.co.uk
              I have become... comfortably numb

beamendsltd wrote:
> 
> In message 
>           Greg Procter  wrote:
> 
> > Dragon Heart wrote:
> > >
> > > My son runs a DCC system using Hornby's Select unit.  He has three
> > > ovals of track on an 8' x 4' surface.  He's been having reliability
> > > problems so I have removed the inner oval to reduce the overall size
> > > of the track run.
> > >
> > > Is there a 'rule of thumb',  guideline or rule that dictates the
> > > maximum run of track for a given size of controller ?
> > >
> > > Chris
> >
> >
> > NO!
> >
> > The length of track is irrelevant to the amperage of power supply.
> > What does matter is the way the electricity gets to the locomotive.
> > Rail joiners are definitely imperfect electrical connectors, so you need
> > feed rails at regular intervals.
> > The further the feeder track from the power supply the thicker the wire
> > connections need to be.
> > A given wire has a specific resistance per foot/metre so a long feed
> > wire will lose voltage - the train runs slower.
> > A second feed section on an oval will effectively halve the resistance
> > between power supply and loco because the electricity then has two
> > paths, both of which get utilzed in inverse proportion to their
> > resistance.
> > I take this system to it's logical conclusion and fit a feed wire to
> > every length of rail - trains run at constant speed anywhere on the
> > layout.
> >
> > Regards,
> > Greg.P.
> 
> It's been a looong time since (40 years..) I used set track, but on
> my Mk.1 cellar layout (Hornby Super 4!!) mixed with Peco (about 20' x
> 16) I just used to nip joiners up with a pair of pliers when laying
> the track to get a good interference fit. This removed all problems
> permenantly and needed only one feed from each controller - it took
> a coupe of attempts sometimes but was much easier that extra wiring.
> 
> Just my 2p.
> 
> Cheers
> Richard

There's nothing difficult about extra wiring :-) Especially compared to
trying to work out why a loco runs fast o one piece of track and then
slow on the next.
Crimped fishplates may well solve such problems instantly, but the
solution is likely to be temporary, particularly if you balast your
track.
Sure, wiring can be tedious, but I long ago concluded that the effort is
worthwhile. A part of that would be that I like to run my branchline
steam locos at scale speeds.

Regards,
Greg.P.

In message 
          Greg Procter  wrote:

> beamendsltd wrote:
> > 
> > In message 
> >           Greg Procter  wrote:
> > 
> > > Dragon Heart wrote:
> > > >
> > > > My son runs a DCC system using Hornby's Select unit.  He has three
> > > > ovals of track on an 8' x 4' surface.  He's been having reliability
> > > > problems so I have removed the inner oval to reduce the overall size
> > > > of the track run.
> > > >
> > > > Is there a 'rule of thumb',  guideline or rule that dictates the
> > > > maximum run of track for a given size of controller ?
> > > >
> > > > Chris
> > >
> > >
> > > NO!
> > >
> > > The length of track is irrelevant to the amperage of power supply.
> > > What does matter is the way the electricity gets to the locomotive.
> > > Rail joiners are definitely imperfect electrical connectors, so you need
> > > feed rails at regular intervals.
> > > The further the feeder track from the power supply the thicker the wire
> > > connections need to be.
> > > A given wire has a specific resistance per foot/metre so a long feed
> > > wire will lose voltage - the train runs slower.
> > > A second feed section on an oval will effectively halve the resistance
> > > between power supply and loco because the electricity then has two
> > > paths, both of which get utilzed in inverse proportion to their
> > > resistance.
> > > I take this system to it's logical conclusion and fit a feed wire to
> > > every length of rail - trains run at constant speed anywhere on the
> > > layout.
> > >
> > > Regards,
> > > Greg.P.
> > 
> > It's been a looong time since (40 years..) I used set track, but on
> > my Mk.1 cellar layout (Hornby Super 4!!) mixed with Peco (about 20' x
> > 16) I just used to nip joiners up with a pair of pliers when laying
> > the track to get a good interference fit. This removed all problems
> > permenantly and needed only one feed from each controller - it took
> > a coupe of attempts sometimes but was much easier that extra wiring.
> > 
> > Just my 2p.
> > 
> > Cheers
> > Richard
> 
> There's nothing difficult about extra wiring :-) Especially compared to
> trying to work out why a loco runs fast o one piece of track and then
> slow on the next.
> Crimped fishplates may well solve such problems instantly, but the
> solution is likely to be temporary, particularly if you balast your
> track.
> Sure, wiring can be tedious, but I long ago concluded that the effort is
> worthwhile. A part of that would be that I like to run my branchline
> steam locos at scale speeds.
> 

All I can say is my method worked just fine, with ballast, flooded with
plaster of paris and any other scenic endeavours! Having been a Wireman
at one stage, I'd still go down the joiners route - for better or for
worse I'm a believer in fixing the cause rather than hiding the symptoms,
but each unto their own and all that.

> Regards,
> Greg.P.

Cheers
Richard

-- 
www.beamends-lrspares.co.uk       sales@beamends-lrspares.co.uk
              I have become... comfortably numb

beamendsltd wrote:
> 
> In message 
>           Greg Procter  wrote:
> 
> > beamendsltd wrote:
> > >
> > > In message 
> > >           Greg Procter  wrote:
> > >
> > > > Dragon Heart wrote:
> > > > >
> > > > > My son runs a DCC system using Hornby's Select unit.  He has three
> > > > > ovals of track on an 8' x 4' surface.  He's been having reliability
> > > > > problems so I have removed the inner oval to reduce the overall size
> > > > > of the track run.
> > > > >
> > > > > Is there a 'rule of thumb',  guideline or rule that dictates the
> > > > > maximum run of track for a given size of controller ?
> > > > >
> > > > > Chris
> > > >
> > > >
> > > > NO!
> > > >
> > > > The length of track is irrelevant to the amperage of power supply.
> > > > What does matter is the way the electricity gets to the locomotive.
> > > > Rail joiners are definitely imperfect electrical connectors, so you need
> > > > feed rails at regular intervals.
> > > > The further the feeder track from the power supply the thicker the wire
> > > > connections need to be.
> > > > A given wire has a specific resistance per foot/metre so a long feed
> > > > wire will lose voltage - the train runs slower.
> > > > A second feed section on an oval will effectively halve the resistance
> > > > between power supply and loco because the electricity then has two
> > > > paths, both of which get utilzed in inverse proportion to their
> > > > resistance.
> > > > I take this system to it's logical conclusion and fit a feed wire to
> > > > every length of rail - trains run at constant speed anywhere on the
> > > > layout.
> > > >
> > > > Regards,
> > > > Greg.P.
> > >
> > > It's been a looong time since (40 years..) I used set track, but on
> > > my Mk.1 cellar layout (Hornby Super 4!!) mixed with Peco (about 20' x
> > > 16) I just used to nip joiners up with a pair of pliers when laying
> > > the track to get a good interference fit. This removed all problems
> > > permenantly and needed only one feed from each controller - it took
> > > a coupe of attempts sometimes but was much easier that extra wiring.
> > >
> > > Just my 2p.
> > >
> > > Cheers
> > > Richard
> >
> > There's nothing difficult about extra wiring :-) Especially compared to
> > trying to work out why a loco runs fast o one piece of track and then
> > slow on the next.
> > Crimped fishplates may well solve such problems instantly, but the
> > solution is likely to be temporary, particularly if you balast your
> > track.
> > Sure, wiring can be tedious, but I long ago concluded that the effort is
> > worthwhile. A part of that would be that I like to run my branchline
> > steam locos at scale speeds.
> >
> 
> All I can say is my method worked just fine, with ballast, flooded with
> plaster of paris and any other scenic endeavours! Having been a Wireman
> at one stage, I'd still go down the joiners route - for better or for
> worse I'm a believer in fixing the cause rather than hiding the symptoms,
> but each unto their own and all that.
> 
> > Regards,
> > Greg.P.
> 
> Cheers
> Richard

Hi Richard,

the 'cause' is incomplete contact. 
Rail joints move because baseboards twist, because wood and metal expand
and contract at different rates, and because we're running mechanical
weights over the joins.
To some degree the movement should cause mechanical cleaning, but in my
experience it doesn't. It does provide a space for oxidation and dirt to
accumulate.
Any three items joined only by mechanical tension under such conditions
are not 'fixed'. Also, a rail joiner has a smaller cross-section than
the rails it joins and so becomes an additional resistance.

Soldering of course is less than perfect, but it works for me,
particularly long term.

Regards,
Greg.P.

On the 'original' three oval layout I wired in two additional track
feeds on the far side but these were 'piggy backed' off the original
which could be my problem !

I think I will keep his layout to two ovals as his Select has only a
limited power output but rewire the second track feed direct from the
Select. It will also give him more room for his goods yard and also
for me to put in an access hole.

Thanks for the advise folks,  it's what I expected,  but it's good to
know other people with greater experience than me in these matters
back up my thoughts.

Chris

In message 
, 
Dragon Heart  writes
>On the 'original' three oval layout I wired in two additional track
>feeds on the far side but these were 'piggy backed' off the original
>which could be my problem !
>
>I think I will keep his layout to two ovals as his Select has only a
>limited power output but rewire the second track feed direct from the
>Select. It will also give him more room for his goods yard and also
>for me to put in an access hole.
>
>Thanks for the advise folks,  it's what I expected,  but it's good to
>know other people with greater experience than me in these matters
>back up my thoughts.
>
>Chris

What wire are you using. So-called "layout wire" is too thin and causes 
voltage drop.
-- 
Jane
British OO, American and Australian HO, and DCC in the garden
http://www.yddraiggoch.demon.co.uk/railway/railway.html

On 14 Jun, 08:35, Jane Sullivan 
wrote:
> In message
> ,
> Dragon Heart  writes
>
> >On the 'original' three oval layout I wired in two additional track
> >feeds on the far side but these were 'piggy backed' off the original
> >which could be my problem !
>
> >I think I will keep his layout to two ovals as his Select has only a
> >limited power output but rewire the second track feed direct from the
> >Select. It will also give him more room for his goods yard and also
> >for me to put in an access hole.
>
> >Thanks for the advise folks,  it's what I expected,  but it's good to> >know other people with greater experience than me in these matters
> >back up my thoughts.
>
> >Chris
>
> What wire are you using. So-called "layout wire" is too thin and causes
> voltage drop.
> --
> Jane
> British OO, American and Australian HO, and DCC in the gardenhttp://www.yddraiggoch.demon.co.uk/railway/railway.html

The live & neutral wires from a 30 amp cable !

Chris

Dragon Heart wrote:
> 
> On 14 Jun, 08:35, Jane Sullivan 
> wrote:
> > In message
> > ,
> > Dragon Heart  writes
> >
> > >On the 'original' three oval layout I wired in two additional track
> > >feeds on the far side but these were 'piggy backed' off the original
> > >which could be my problem !
> >
> > >I think I will keep his layout to two ovals as his Select has only a
> > >limited power output but rewire the second track feed direct from the
> > >Select. It will also give him more room for his goods yard and also
> > >for me to put in an access hole.
> >
> > >Thanks for the advise folks,  it's what I expected,  but it's good to
> > >know other people with greater experience than me in these matters
> > >back up my thoughts.
> >
> > >Chris
> >
> > What wire are you using. So-called "layout wire" is too thin and causes
> > voltage drop.
> > --
> > Jane
> > British OO, American and Australian HO, and DCC in the gardenhttp://www.yddraiggoch.demon.co.uk/railway/railway.html
> 
> The live & neutral wires from a 30 amp cable !
> 
> Chris

Half inch brass bus-bar is better!
;-)

Greg.P.

Greg Procter  wrote in
news:48544EC5.6C83F484@ihug.co.nz: 

> Dragon Heart wrote:
>> 
>> On 14 Jun, 08:35, Jane Sullivan 
>> wrote:
>> > In message
>> > <93bf5cd1-b420-4bab-a8b4-1d974df91...
@e53g2000hsa.googlegroups.com>,
>> > Dragon Heart  writes
>> >
>> > >On the 'original' three oval layout I wired in two additional
>> > >track feeds on the far side but these were 'piggy backed' off the
>> > >original which could be my problem !
>> >
>> > >I think I will keep his layout to two ovals as his Select has only
>> > >a limited power output but rewire the second track feed direct
>> > >from the Select. It will also give him more room for his goods
>> > >yard and also for me to put in an access hole.
>> >
>> > >Thanks for the advise folks,  it's what I expected,  but it's good
>> > >to know other people with greater experience than me in these
>> > >matters back up my thoughts.
>> >
>> > >Chris
>> >
>> > What wire are you using. So-called "layout wire" is too thin and
>> > causes voltage drop.
>> > --
>> > Jane
>> > British OO, American and Australian HO, and DCC in the
>> > gardenhttp://www.yddraiggoch.demon.co.uk/railway/railway.html 
>> 
>> The live & neutral wires from a 30 amp cable !
>> 
>> Chris
> 
> Half inch brass bus-bar is better!
> ;-)

You always have to have the last word (waits) ;-)

-- 
All the best,

Chris Wilson

email to cwilson at britwar dor co dot uk, reply address is spamtrapped.
http://www.the-dormouse.org The Dormouse Line model railway

Chris Wilson wrote:
> 
> Greg Procter  wrote in
> news:48544EC5.6C83F484@ihug.co.nz:
> 
> > Dragon Heart wrote:
> >>
> >> On 14 Jun, 08:35, Jane Sullivan 
> >> wrote:
> >> > In message
> >> > <93bf5cd1-b420-4bab-a8b4-1d974df91...
> @e53g2000hsa.googlegroups.com>,
> >> > Dragon Heart  writes
> >> >
> >> > >On the 'original' three oval layout I wired in two additional
> >> > >track feeds on the far side but these were 'piggy backed' off the
> >> > >original which could be my problem !
> >> >
> >> > >I think I will keep his layout to two ovals as his Select has only
> >> > >a limited power output but rewire the second track feed direct
> >> > >from the Select. It will also give him more room for his goods
> >> > >yard and also for me to put in an access hole.
> >> >
> >> > >Thanks for the advise folks,  it's what I expected,  but it's good
> >> > >to know other people with greater experience than me in these
> >> > >matters back up my thoughts.
> >> >
> >> > >Chris
> >> >
> >> > What wire are you using. So-called "layout wire" is too thin and
> >> > causes voltage drop.
> >> > --
> >> > Jane
> >> > British OO, American and Australian HO, and DCC in the
> >> > gardenhttp://www.yddraiggoch.demon.co.uk/railway/railway.html
> >>
> >> The live & neutral wires from a 30 amp cable !
> >>
> >> Chris
> >
> > Half inch brass bus-bar is better!
> > ;-)
> 
> You always have to have the last word (waits) ;-)
> 
> --
> All the best,
> 
> Chris Wilson
> 
> email to cwilson at britwar dor co dot uk, reply address is spamtrapped.
> http://www.the-dormouse.org The Dormouse Line model railway