Recessing switch rails on LGB turnouts

A

Andrew_au

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I notice several of my LGB turnouts have a minor design flaw. When the switch rail is placed against the stock rail, it sticks out very slightly. This has a couple of issues:
  • the flanges on some of my single-axle wagons clip the switch rail, causing an uneven transition through the turnout as the flange kicks sideways off the tip of the switch rail.
  • the LGB turnout drives do not "lock" after they have finished throwing. With enough vibration, the switch rails drift away from the stock rails causing derailments.
    • Some third party drives lock, either mechanically or by continuing to apply trickle power after finishing their throw. Manual LGB turnout levers contain a spring mechanism that continues to apply pressure once the turnout is thrown.
If you look closely at the turnouts, there is usually a cut-away so the switch rail can recess into the stock rail. However, this cut away doesn't extend to the top of the stock rail where the switch rail touches it. It's more of a problem when the turnout is not completely supported across its entire length. Sometimes the support is different on the switch and stock rails causing the switch rail to raise very slightly.

To counter this, I was thinking about filing or grinding away a small recess in the stock rail so that the tip of the switch rail can fit entirely into it. Thus, the approaching wheel never sees the edge of the switch rail.

This will leave a slight edge on the stock rail when the point blade is open, but that shouldn't be an issue as the main profile of the rail is intact, the lip can be smoothed, and most of the pressure is away from (rather than towards) the stock rail.

Thoughts?

Any idea on the best tool for the job? I don't want to disassemble the turnout, so I basically have to get a file or rotary disc into the gap between the open switch rail and the stock rail. I also only want a very shallow indent, 0.5mm or so.
 
To answer your second issue LGB turnout drives do not "lock" after they have finished throwing. LGB point do NOT have an over-centre spring like Piko, but and designed to be used with either the manual or electric switch, both of which will hold the blades in place. When sold new LGB points come with one or other of these, but second hand, they are often missing.

New manual point
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The 12060 manual turnout mechanism is spring loaded. Unless it has changed very recently, the 12010 electric turnout mechanism (EPL drive) allows the switch blades to move freely once power is removed.

I recently had a couple of 12010 drives which had ceased to function, so I took them apart to see if I could fix them. One just had a bit of dirt and rust fouling the mechanism. The other had an entire ant colony (about 20 ants and 50 eggs) that somehow was still alive despite sitting in a sealed box on my desk for 6 weeks!

The 12010 mechanism is delightfully simple. The switch bar is driven by a rack and pinion mechanism. The pinion is attached to a sealed cylinder containing a weak permanent magnet. This magnet rests between a pair of metal plates that come together in a U shape. The power wires from the inputs are wrapped in a coil around the base of the U.

Power the wire in one direction and the plates polarise one way, rotating the pinion and moving the bar. Power the wire in the opposite direction and the plates polarise in the opposite direction, causing the pinion to flick back the other way. It's basically a DC electric motor. But without any brushes or other mechanism to flip the polarity to cause continual rotation it stops dead after half a cycle.

This is a very simple system that is resilient against weather and decay. The wire coil is sealed, the plates can handle a bit of corrosion, and the only moving parts are the magnetised barrel and the rack-and-pinion connection to the throw bar, both of which are decent quality plastic and pretty robust as long as you don't break a tooth.

However, this also means that once power is removed the only thing holding the bar in place is the mass of the components involved and the friction inherent in the system, none of which are particularly significant. If your switch blades would naturally rest not flush against the rail then they will fall back there as soon as power is removed. Mechanically, it might have been a better design to cause the drive to throw a spring-loaded switch as in the manual mechanism, but that adds additional points of failure.
 
Andrew_au said:
Thoughts?
Click to expand...

Unless you are actually having continual problems with a bunch of LGB turnouts, it seems to me you may be way overthinking this. I have had a bunch of LGB turnouts from various eras of production and have never had any issues, indoor or outdoors, with the seating of the blades with the stock rails when using LGB point motors.

FWIW, if you are having issues with long wheelbase two-axle wagons the way to address that is on the wagons rather than with the track.
 
Andrew_au said:
I notice several of my LGB turnouts have a minor design flaw. When the switch rail is placed against the stock rail, it sticks out very slightly.
Click to expand...
I've had this problem with several turnouts and it is easily resolved by using a cut off blade in a dremel (or similar tool). I wouldn't touch the running surface of the stock rail. Much easier to work on the moving point blade, removing material from the top of the tip to allow the blade to tuck under and into the stock rail without any protusion.
AL
 
I have a LGB R3 point where the slider support under the blade had dropped, and when the bade moved across it was tucked under the main rail, causing the gauge to be slightly wide, and as such the side of some wheels would jam. Difficult to describe, but levelling up the blade with packing did the job.
I have another LGB R3, where a number of locos and wagons occasionally derail when running into the point and taking the curved route, can't find anything wrong with the point, and have other that are the same type and no issues, just this one, and only sometimes!!
 
In my experience, one of the biggest causes of problems with points (turnouts) is twist, or not being level across the track. - Before, through, and after the point.

I would have a hard look at this, before modding the point. - You can not replace any material you remove, easily.

PhilP
 
I have corrected 2 issues with my LGB points/switches.

The alignment of the drive inside can be off by one gear tooth and create an issue with not being thrown fully in one direction.

Also if switch is not perfectly level then there is added tension which prevents the points being thrown all the way.
 
Dan said:
I have corrected 2 issues with my LGB points/switches.

The alignment of the drive inside can be off by one gear tooth and create an issue with not being thrown fully in one direction.

Also if switch is not perfectly level then there is added tension which prevents the points being thrown all the way.
Click to expand...
That can be easily resolved by taking the top off then adjust the rack.
 
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