BASIC TRACK PLAN EXPANDED WITH AN ADDITION
(And how to wire it for DC ) Plus (WIRING A REVERSING SITUATION)
Taking a look at this track plan, you will see there has been a completely new addition added. This addition measurers 30 inches X 96 inches (8 feet). (croll down for the rest of the article.)
Bill of Material:
1 - #4 Wye Turnout
5 - #4 Left Hand Turnouts
3 - Right Hand Turnouts
Approximately 14 pieces of 36in. flex track
3 - 8 space terminal boards 7 - Single Pole Double Throw Center Off switches (2 more than Track Plan 2)
4 - Double Pole Double Throw Center Off switches
With the addition of one more #4 Left Hand Turnout, you can make an engine storage track in the yard and use the same SPSW switch to feed it as in Track Plan 2. See dashed line on drawing.
If you compare this track plan with Track Plan #2, you will notice that some of the insulated rail joiners have been moved slightly and a couple of new ones added.
Also, new blocks have been added in the basic track plan, and the on/off switch removed and the engine storage track turned into a industrial spur. The entire addition since it is a switching layout has been made into just one block, block #7. Well, there is one exception, we now have a block number 8 which is shown in red.
What was the interchange track on Track Plan 2 is now one leg of a "Wye" and will take very special wiring. This Wye is a reversing situation, which means a train entering the addition in one direction can exit the addition and be running in the opposite direction once it is back on the basic layout.
Please note that the red marking for insulated rail joiners is different to this reversing leg of the Wye as both rails must be insulated and at both ends of the track. If you do not want to go to the extra work of putting in a reversing situation, simply eliminate the #4 Wye Turnout and just shorten the interchange track to fit. Either way will allow you to still run two trains at a time and have a lot of fun doing it.
WIRING A REVERSING SITUATION
There are many different ways of wiring a reversing situation. It can be done somewhat automatically if you mount auxiliary contacts on one of the turnouts connected to the wye. If your power packs have a set of reverse loop terminals, this is by far the easiest. However, very few power packs have this feature built in. For our purposes we will explain how to wire the layout for manual operation.
As with the electrical switches mention for Track Plan #2, there are a couple of manufacturers who build switches for just this purpose. These are available from your local hobby shop and you will only need two. Just follow the manufacturers instructions and away you go. However these manufactured switch units do not look as neat on a control panel as Double Pole Double Throw Center Off (DPDT) toggle switches do.
For the purposes of this explanation you will need four (4) DPDT Center Off switches and one more 8 position terminal block. All of these switches will need to be wired as in this diagram. Do not confuse the terminals on these drawings marked A and B, with Cabs A and B. The As and Bs on the drawing are just showing the wire placement on the lugs of the switches.
First set the directional switch on your power packs following the right hand rule. Then put electrical tape over those switches so they can't be moved again. Two of these DPDT switches will now become the reversing switches for the seven blocks of your layout and the other two will be used as the reversing switches for one leg of the Wye.
To save confusion when wiring in these new reversing switches we recommend you only do one cab at a time. This way there will not be a lot of loose wires hanging that could cause you confusion when hooking everything back up.
As mentioned above, pre-wire the switches leaving enough wire to reach your power packs and terminal boards. First disconnect the two wires from the terminals of Cab A going to the terminal boards. Run two new wires to the 3rd terminal board from the terminals on the power pack and call them Cab A Power. Jumper from these two terminal board screws to the pair right beside them and mark those Cab A Reverse.
Now connect the two wires coming from the center lug of the layout reversing switch to the other two screws on the Cab A Power terminal spaces. Connect the two wires you originally took loose from Cab A to the two wires marked "to track" from the reversing switch. You can do this with wire nuts or use empty spaces on any of the terminal boards, just be sure the connection can be taken apart with out using a soldering tool.
Now do the same thing for your Cab B wiring. When finished your direction control on the layout will be the same as it was before except you will be using these two new switches to change the direction.
We will now hook up the two reverse loop (Wye) switches. First connect the center two wires from the Cab A reversing situation switch to the two terminal board positions you marked Cab A Reverse. Terminate the two other wires to two different terminal positions on the terminal board and mark this Cab A Reverse Out, or some such language. Now do the same for Cab B.
Run two-track feeder wires from your reversing block of the Wye, Block
number 8, to the terminal board positions marked Cab A Reverse Out. Leave
enough wire so all you need to do is strip off a portion to loop around
the terminal screws for Cab A and terminate the remainder to the Cab B Reverse
Out terminals. You are finished!!
After installation of all the switches and wires, be sure to keep both of the reversing switches for the reverse leg of the Wye in the center Off position until you are ready to run a train through this leg. Keeping both of these switches in one of the on positions will not cause a problem till you actually run a train over that track. If they are both on and set for opposite directions you will cause a short across the winding of your engine, and we don't want you to burn the motors out.
The other new block switches are to be hooked up just as you were told in the wiring instructions for Track Plan #2. Since we recommended bare wire between the other block switches (This is now known as a "bus") you can tap the new feeder wires at any convenient spot for soldering.
If you decided to do any further expansion to your layout we have covered almost all of the wiring situations you may get into. The only exception is if you want to use more than two power packs you will need to replace all of the toggle switches with rotary switch.
As you can see the wiring of a model railroad can be somewhat complicated.
Since you are just starting out we recommend you take a very serious look
at DCC as the wiring is much simpler.