| AC/DC Universal layout
I am building an universal layout in order to run DC locos and Marklin locos on
the same track system without modifying the locos in any way.
The reason is that I am an experienced modeller in DC system ( 25 years ) and
now to something new I want to enter the fantastic Marklin world but I also
want to use again my moreless 100 DC locos .So I have decided to build
an universal layout .
- 2 rail system and 3 rail system on the same layout
- no modifications of locos and rolling stock
- use of the same power supply system (optional)
- very simple modifications on the track system
It must be noticed that it’s impossible to operate AC and DC at the same time!
After reading Marklin Magazine C Gleis Spezial book ( Marklin catalog No 188987) in
which the author Markus T. Nickl explains very well all the tips of the C track ,
I decided that this was the right track system for my purpose.
The rasons of this choice are the following :
- Ready ballasted track
- Profile height 2,3 mm (code 90 ) . It’s a good compromise between realism and operation
- Easy insulation of the rails . This is a must for DC operation . Tracks are designed to be insulated for AC automatisms ; there are two jumpers for each track section that can be cut using nippers .Refer to Marklin Magazine C Gleis Spezial for this matter.
- Metal frogs . This is very good for DC operation and digital operation both for DC an AC. At this point I had the problem to insulate the turnouts and feed the frogs for DC operation.; so I bought a turnout to study the easiest solution.
How to insulate and feed Marklin C turnouts for DC operation
After some experiments I found a quite simple solution .
To have always good performance mechnical and electrical modifications are required .
In order not to destroy the marvellous Maklin turnouts mechnical modifications are very simple and so it’s better to work on electrical wiring .
First of all it’s necessary to cut the two metal connections between the points of
the turnout and the outer rails; to do this I use Dremel tool equipped with a very thin disc saw.
I can assure that the cuts are moreless invisible and that the mechnical integrity is the same as before. At this point you have obtained a so called “power routing turnout “absolutely the same from the electrical point of view , as a Peco electrofrog turnout .( see Peco catalog for this point)
Now it,s necessary to feed the frog according the position of the turnout ( you have to change the polarity of the frog when you change the position .Generally it’s a very simple operation if the switch machine is equipped with auxiliary contacts ,but unfortunately Marklin switch machine has no this option .So to feed frogs I have connected the coils of two monostable relays between blue wires and brown wire in order to have a perfect syncronisation with the coils of the motor and the coils of the relays
You can do this because Marklin switch machines are equipped with power shutoff switches.
Connect the frog to the center pin of the relays and the DC supply to the “ normaly open “pins of the relays according the polarity of the outer rails .In case of short simply reverse the polarity of DC feed . Now everything will work in the right way .
It must be noticed that:
- Turnout motors must be supplied with 15V DC because the low voltage relays are designed for DC operation .
- DC coil resistance of the relays should be 700- 800 Ohms.
It’s very easy to find this kind of relay in every electronic shop and the price is not expansive
( I have paid them 2.5 Euros each ).
- In my layout I use only normal turnouts , so I don’t know exactly how to operate on double slips and 3 way turnouts but I think it shold be very simple because these turnouts seem to be already insulated.
In any case I suggest to refer to this book for all tips concerning DC wiring :
Andy Sperandeo - Easy model railroad wiring – Kalmbach Editions.
Using the same power supply system for DC and AC operation.
The worst enemy of every model railroader is the the space ; infact I had no sufficient
space to install other two DC trasformers in my layout .
The solution was to use an electonic step relay in order to use the 24 VAC pulse supplied by Marklin trasformers to reverse the polarity and to rectify the AC variable voltage.
Hag and Roco has these devices ready to run ; they are designed to transform DC lococ
for Marklin system . I have purchased two devices by Hag ( 25 Euros each) and I have simply connected them between Marklin trasformers and the rails when I use DC locos:
everything works in the right way .
It must be noted that these devices are designed to operate directly on a DC motor so
to have a good overload protection I use the Marklin device No.74046 in series between
Hag reverse unit and the rails.
Till now I have made some test using old Fleishmann and Hamo locos because
they are equipped with high flange wheels ; I am very satisfied : they run very well on the turouts !
So now when I want I use DC and AC locos in the best way .