I’ve recently purchased a Lionel Train Set and have thought about expanding it a bit.
I come from HO scale and use a DCC (Digital Command Control) system which allows independent control of any decoder equipped locomotive.
In HO reverse loops create a short condition unless you use an automated reversing module or go the manual way and use toggle switches to change the polarity of the track.
My question is: because Lionel uses three rail with the middle rail never coming in contact with the outer rails, is there anything necessary that you need to do to have a loop to loop type layout? Is there any possibility of a short? If so please explain. I think I have tunnel vision and am missing something.
Bill, welcome to O gauge! Lionel track uses three rails for regular O gauge, there is two rail O gauge but the trains need insulated wheels to run on that similar to H.O.
The only thing that you may want to do is put an insulating pin in to separate track blocks, put the pin in the center rail, remove the metal pin and install the insulated pin. This can be done with a flat tip screwdriver & a pair of pliers, use the screwdriver to open the track from the bottom and then pull the pin out with the pliers, it will take some effort. Not sure how to insulate Lionel’s new Fastrac though as the pins are differant than tubular track.
As in H.O. there are several companies that make track & switches for three rail O gauge. Lionel, MTH, Atlas O, Williams by Bachman, Ross Custom Switches, GarGraves track & switches. Also DZ Industries makes switch motors for Ross & GarGraves track.
Speaking of GarGraves track there is a major differance with this brand of track and that being that all three rails are insulated or have power seperated from each other. Most of the other brands have the two outer rails sharing the same electrical path. Some people like GarGraves for looks, others because you can seperate the outer rails and make an accessory self activating by using a common or return wire from the outside rail. Another thing about GarGraves and Ross switches is that the motors can be taken out and the track left in place when a switch motor goes bad.
In O gauge there are two major command control systems from two competing companies, Lionel and Mike’s Train House(MTH). Lionel has licensed the sale of TMCC(Lionel’s brand) to other companies. MTH has DSC or PS-2 as some people call it. Only TMCC equipped units can be controlled by TMCC, TMCC may control a couple features of a DCS equipped engine but not all, same thing for DCS. To run both from what I have read and know about you nee
There is nothing needed to make a loop to loop layout except two turnouts (switches) and track.
With three rail track there is no way to bring the loop back upon itself and create a situation where the powered rail feeds into the common/ground causing the polarity to cross/mix - as can happen with two rail track. The current from the middle rail will never connect into into the outside ground/common rails unless you have a defective section of track.
(The only minor caveat to this is when working with cross over pieces (90 degrees, 45 degree) in a layout with different blocks controlled by different transformers. In this case you may need to desolder a portion of the middle rail underneath the crossover and insulate it to keep blocks isolated.)
Three rail turnouts/switches are designed to isolated the middle rail from the outside rails. So a turnout will never create a situation where the power feeds back upon itself causing the polarity to cross/mix.
The turnouts also offer a “non-derailing” feature where they will automatically flip to the correct position when a train approaches.
So a basic loop-to-loop layout is actually one of the easiest and simplest to construct. It can be run non-stop without any need to control the turnouts. As a train approaches a turnout, the turnout will flip to the correct position. As the train moves around the loop and approaches the turnout from a different side, the turnout will flip to the correct position.
For reverse loops you don’t need anything special, that’s what I love about 3rail, as long as the track sections line up reasonably straight they will run. If the set that you purchased is a fairly recent vintage it more than likely came with the Lionel Fastrack. This system is very kid friendly, easy to assemble, and if you start out running on the carpet the plastic roadbed makes it also very spouse friendly, no grease or oil on the carpet. As well as no carpet fibers in the axles/gears. My only issue with the Fastrack is it can be a bit costly if/when you expand and on bare floors(tables) it can be noisey. [#welcome]
Bird is correct here about the “non-derailing” feature of Lionel turnouts. I know this is true for the remote controlled turnouts, but not being familiar with the manual type, I’m not sure that "non-derailing feature is built into them. Like I said, I’m not sure, so this may not be worth bringing up. Ken
It’s done with what’s called a “control rail”. That is a short piece of the outside rail that is isolated from the rest of the outside rails. As the train approaches the turnout (in the trailing-point direction), its wheels connect the control rail to the other outside rails, completing an electrical circuit which operates one of the turnout’s actuating coils.
This same trick is, or can be, used to operate many of the trackside accessories on 3-rail layouts, like crossing signals and gates. It’s the very same concept that prototype railroads use to operate their crossing signals and automatic block signals, ironically making 3-rail track in a way functionally more prototypical than 2-rail!
To answer your question, no. That’s the beauty of O-gauge, no polarity changes. The center rail is always the positive (+) rail, and the two outer rails are negative (-). Train direction is controlled with an e-unit, inside the engine. This changed polarity to the motor internally.
On the newer models of locomotives you are correct, as the newer ones use D.C. If you want to make a new loco go forward only and it don’t have a lockout switch(Williams mainly) you can take out the circuit board and put in a bridge rectifier(6 amp) straight to the motors.
On the older locomotives(1970’s and earlier, maybe up to 1980’s) the e-unit changes the current to the feild or motor windings, could be a bit more but basically that’s what I think the old e-unit does.
For the remote control it is an automatic non-derailing feature, however it is my understanding that the “manual” turnouts will operate on a run-thru basis. The points being spring loaded so the train will force them open as it “runs-thru” and they will return to their previous position. This being a common feature on Atlas
Although Lionel-style trains will run just fine with the center rail always positive and outside rails negative, they have usually been run on AC, since the early twentieth century.
To change direction, the e-unit swaps the brushes of the series-wound universal motor, or switches between two sections of field winding, or reverses the polarity of the voltage supplied from a bridge rectifier to a permanent-magnet DC “can” motor.