uncoupler track sections question

Most O gauge couplers (The big ones called lobster claws by some.) have a tab that hangs low just above the center rail.  Uncouplers are electromagnets.  You do your best to line up the tab on the coupler with the center of the uncoupler.  When you push the uncouple button it sends a current to the uncoupler making it magnetic and it pulls the coupler tap towards the track which pops the coupler open.  You'd use them in places you'd want to leave cars behind, so switching yards, spurs, both ends of a siding, things like that.  As for location, depends on where you want to leave cars.  Experience has found you don't want them right up next to a switch.

I use them on sidings so that I can drop off and pick up cars....  As "sinclair" noted.. placing one too close to a switch will cause an accident, also keep in mind that immediately next to curve piece of track can be a problem too...  when you are dropping a car off with the uncoupler, the coupler you open on  the freight car your leaving behind will be sitting right over the magnet.  

 When you come back in to hook up the couplers through a curve section of track after the switch, the couplers may not line up and engage each other, this problem gets more severe with sharper curves.  Best to have some cars handy when you're laying the track, open the coupler park it on the siding and see if when you roll the next car in, the couplers line up....  Hope that helps.    

Several years ago, Jim Barrett had an article in OGR magazine where he discussed how to remove Lionel uncoupling magnets from their original track sections and cutting out a small section of Gargraves track and inserting them there. The magnets blended in well once installed and worked well. I used them on my last switching layout. The article reran at least one more time more recently. The old track sections with the magnets can be found on eBay rather inexpensively, I think I bought 40 for around $20 back around 2001. You can also find them at local train shows.

Tom

if you can get your hands on Lionel Super O uncouplers this works without the work described above.

Any Momentary switch controls them and I think you can get them relatively low cost - in the model train hobby nothing is cheap 

Atlas track un-couplers.   Note that it adds a small hole in the center track power.

Note that this device picks track common and requires power to a momentary push button to energize the coil.  Hold too long you could burn the magnetic coil. IMO  I believe these are provided with the push button.

Thumb tack uncouplers. Top is an electro-coupler.  The magnet pull the thumb tack down, releasing the coupler jaw which is spring loaded.

Additional note. On the Fort Pitt Hi-Railer Time saver modules there are several un-couplers, older, maybe Gargraves. Basic wiring is relatively simple as noted. It was interesting to note that these devices can draw a lot of current to operate. We eventually use a spare Z4000 track circuit to power them. At that point we could reliable open the thumb tack couplers. IMO. Mike CT

Here's a picture of my TimeSaver. I used GarGraves. The black rectangles in the track are the uncouplers.

Gilly