Accessories - Track

The various track accessories needed for O gauge operation are listed here.  Most of them had corresponding items in the postwar line.

450 Track Terminal

The O gauge version looks just like the 690, but smaller.  There was no equivalent of the 707.  Dual-gauge versions are common.

540 Directional Control Button

This is essential for running DRC locomotives or the Whistling Baggage Car.  The original has a rather complicated mechanical layout, so that contacts are made in sequence as the button is pushed down.

The main problem is that the original selenium pile rectifier has probably gone bad, so it needs to be replaced with a modern diode.  You can just leave it in place and wire around it.  Any diode will do, a rating of 4A is plenty since it's only used intermittently.  The direction doesn't matter.

If you can't acquire an original control, Doug Peck's site has instructions for building one from scratch.

602 Crossing

Tracks are 15" in length.  Center rails are isolated from each other.

604 Crossing

The 604 was mechanically the same as the 602, but included three Fahnstock clips: one for the common outer rails, and one for each of the center rails.  With the control box, which had two NC SPST buttons, two intersecting loops could be controlled.  By pressing the correct button, you stop one of the trains before a collision occurs.  By not pressing the correct button, you may need a new locomotive.   Thanks but no thanks.

610 Bumper

These are difficult to find, and it seems that the casting was a weak design, as surviving examples are often broken.

665 Manual Switches

See below under 688 Remote Control Switches.

675 Uncoupler

The uncoupler is permanently built into a straight section.  With three-rail track, only one wire is needed.  Yellow is the most common color for the coil cover.  The uncoupler had a tall mast which was supposed to help a distant operator spot cars for uncoupling, but the masts got lost easily and originals are very rare.  The mast shown here is a homemade repro.

Here is the grey version, with the original mast.

There was also a manual uncoupler.

677 Track Trip

This is a contact strip that is wedged between the center and outside rail on a straight section.  The metal wheels on all locomotives and cars make contact with the strip and connect it to the base post.  That is somewhat limiting, I must say.  Used in this case to activate the 577 Whistling Billboard, it could also be used with the Talking Station, the Block Signal, etc.  There was nothing like this in the S gauge line; it was replaced by either the 696 or 697.

There was a similar but shorter trip made for use with the Bell Danger Signal.  It doesn't seem to have had a catalog number.

683 Unloading Track

This is the contact rail for the Army Unloading Car and the Dump Car.  It's permanently fastened to a straight section, and corresponds to the 710.

684 Mail Track Set

The mail track set consists of an Unloading Track with a mail stanchion added, for use with the Mail Car, of course.  It corresponds to the 711.

688  Remote Control Switches

These seem to have undergone several incremental changes from the Chicago originals.  There are several ways in which the power to the center rails can be wired, for instance.  Of course, the power will be always applied to the selected track at the wide end of the switch.  The other track can be:

1) Always live:

2) Grounded

3) Floating

4) A lever to choose between 1) and 3), similar in purpose to the little button on S gauge switches:

The switch pictured at top is type 2), and has an extra ground terminal which must be a modification by a previous owner.  If you have a passing siding with type 2 switches, and the switches are not set the same way, you have a short, and that prevents any train from moving.  I guess that's a feature.

All RC switches had two bulbs, red and green, lighted by track power to indicate the position.  The operating mechanisms are generally pretty reliable.

From a maintenance standpoint, the weak point of the design seems to be the little spring contact under the point end of the movable "frog".  If this doesn't make good contact, nothing will work right.  You can glue a small piece of foam rubber or sponge material underneath to keep it pressed upward: