LGB Mikado Derailments

JimmyB said:
Mike, I believe it is the Piko that has the spring, which should be removed (according to their instructions) is a motor is added. The LGB blades are held in place by the external manual control or motor.
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I have to concur with Rhino I'm afraid Jimmy. I didn't have anything other than LGB to start with (it would have been pre-PIKO G scale anyway). Mind you it was a long time ago and they would mostly have been early 'first issue' jobs. I've probably still got them at the bottom of the track box. Might still be worth popping the ramp off anyway just to see.
 
pmindigo said:
Any tips on sharpening the tongue flange tip so they seat tighter to the rail?
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There are a couple of things I've done to tweek the point rails on a few LGB R3 turnouts that were giving me trouble. First, some of the point rails I've run across were seemingly not machined correctly. They have a bit of a blunt end wheel flanges can bump against. A good quality sharp metal file can be used to sharpen the tip of the point rail so it better mates to the milled out bit of the running rail. A second thing I've run across is a slight twist to the point rail such that the running surface doesn't want close tightly against the running rail. This seems to primarily affect the curved diverging point rail. I solved this by grasping the point rail near the middle from above with a standard pair of pliers. Then, with a second pair of needle-nose pliers, grasping the point rail end on and giving it a slight outward twist. I had to be careful though, not to break it from the throwbar.

JimmyB said:
The LGB blades are held in place by the external manual control or motor.
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I believe Jimmy is correct about how LGB point blades have always been kept in position. At least from the early 1980s on. If the motor or manual control is removed the points just flop around. I even pulled out a very old LGB R1 point with a twin-coil drive to check. The twin-coil drive and the manual operating mechanism have an internal spring that keeps the points positioned. The EPL drives use the rather weak magnetic force within the drive motor to keep the points positioned. This is why (in my experience) EPL drives cannot be relied on to return to their set position when run through backwards unlike the manual mechanism and old twin-coil drives.
 
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Rhinochugger said:
I'm pretty sure that the LGB points in manual mode have the over centre spring that Mike mentions - I got rid of mine a good while back, but as they were the first G scale points I had, I do remember ................. :nod::nod:
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ebay mike said:
I have to concur with Rhino I'm afraid Jimmy. I didn't have anything other than LGB to start with (it would have been pre-PIKO G scale anyway). Mind you it was a long time ago and they would mostly have been early 'first issue' jobs. I've probably still got them at the bottom of the track box. Might still be worth popping the ramp off anyway just to see.
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I have just been to check on my points, and the Piko point have holes in the tie-bar and adjacent sleeper, where the over-centre spring has been removed, due to a motor being added. The LGB have NO hole, which is why you have to have these attached if not motorized, to hold the blades in place.

LGB 12060 Manual Point switch x2/Chalk Garden Rail

Manual Point/Turnout Switch x2
www.chalkgardenrail.co.uk
 
pmindigo said:
3rd or 4th set split the tongue flange which is not seated tightly to the rail.
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Surely you must resolve that issue first, you've got no chance if the blade is not inset into the stock rail. A Dremel with a cut-off blade would be your friend for 'adjusting' the rails.

I've took the opportunity to give one of my Mikados i'ts yearly service and photo the leading truck. The spring is a compression type and if you need dimensions let me know.

IMG_20220428_104236197.jpg

The articulation of my Mikados was very stiff when I first acquired them and I thought that the stiffness could cause problems. I removed the chassis from the upper part of the loco and lubricated all of the pivot and sliding points. The front pivot is easy and may be lubricated without dismantling. The rear pivot is completely hidden. The center pivot, between the 2 motor blocks consists of a lower pivot that is easy to see and a similar upper pivot that can only be accessed by removing the chassis. The leading truck also needs lubricating where it slides across the fulcrum just to the left of the LGB sticker.

Now that the pivots are lubricated, with the loco upside-down the chassis flexes very easy without any 'stickiness'.

If your chassis is 'sticky' could that be adding to your problem? If the chassis is resisting articulation the center drivers may be pushing against the point blade?

Removing the chassis involves removing the front and rear trucks (not essential but less to handle), the front pivot screw and 2 screws at the rear where the chassis attaches to the pivot below (looking from underneath). There are 2 pairs of wires to the motor and a pair of plug-in connectors for sound trigger and chuff sensor.

Alan
 
JimmyB said:
I have just been to check on my points, and the Piko point have holes in the tie-bar and adjacent sleeper, where the over-centre spring has been removed, due to a motor being added. The LGB have NO hole, which is why you have to have these attached if not motorized, to hold the blades in place.

LGB 12060 Manual Point switch x2/Chalk Garden Rail

Manual Point/Turnout Switch x2
www.chalkgardenrail.co.uk
Click to expand...
Yep, mine had those but, there's something in Mike's post about the little hump of plastic in the middle of the sleepers .................

maybe the memory is failing, as I say, I got rid of mine a good while ago.
 
Assuming the OP has other long-ish wheelbase loco's.
And, assuming it is only the Mikado causing problems..

Yes, check the geometry of the track, and operation of the point.
But it does point to problem(s) with this particular loco?
 
PhilP said:
Assuming the OP has other long-ish wheelbase loco's.
And, assuming it is only the Mikado causing problems..

Yes, check the geometry of the track, and operation of the point.
But it does point to problem(s) with this particular loco?
Click to expand...
Could be a bit of both :nod:
 
Trying to simulate this problem of the LGB Mikado derailing, I removed the point motor of one of my facing points.

The loco ran for over an hour without derailing. But.......

Watching the throw bar I could see that sometimes it would start to move when the 4th driver was nearing the pivot of the point blade. The trailing truck was just before the start of the point blade. The point blade only moved a fraction, less than a millimetre and didn't cause a derailing problem.
Running the loco at a faster speeds there was less chance of movement of the throw bar.
Running at a slow speed was more likely to move the throw bar. (Wish that I knew how to upload videos)
I checked the back to back on the loco and all axles were 40 mm.

Stopping the loco just before the point and then sliding it forwards (this loco will not roll) caused the point blades to separate massively.

The reason that the point blades move is due to the 4th driver axle moving sideways as it nears the pivot point of the point blade.

I can only see 2 possible reasons that the 4th axle moves sideways -
- The lead truck is entering a curve immediately after the point and is starting to turn the loco chassis.
- The traction tires on the 4th axle are slightly smaller diameter than the actual wheel diameter. The traction tires on this loco are getting old now and have perhaps worn down.
- The significance of the traction tires is that there is effectively a groove in the 4th drivers. the groove gets caught by the rail head and the larger diameter of the outer wheel edge drags the point blade across.

I shall obtain some new traction tires.

Is this only a problem with the LGB Mikado?

The timing and crucial thing is that the trailing truck hits the point blade just after the 4th driver has moved the blades. Unusually long distance between the two.

I was interested to see if there was an issue with fully floating point blades, with no motor or over-center spring for control as I ran a reversing loop with with an uncontrolled point for many years without any problems.

pmindigo said:
These switches are older LGB R1 and R3 models with motor drives
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Do you have problems with several switches? Can all of them be problematic?
This is why I was looking at the Mikado.

You need to check that your switches are all throwing correctly.
Rhinochugger said:
I seem to remember that one of the issues with the LGB Mikado is the pivoting drive chassis that has a tendency not to fully straighten out on the straights
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That's why I suggested lubricating the chassis pivot points and all it's sliding surfaces. If the chassis is not straightening it may be adding to the tendency that I discovered today.

Alan
 
AlanL said:
Surely you must resolve that issue first, you've got no chance if the blade is not inset into the stock rail. A Dremel with a cut-off blade would be your friend for 'adjusting' the rails.

I've took the opportunity to give one of my Mikados i'ts yearly service and photo the leading truck. The spring is a compression type and if you need dimensions let me know.

View attachment 297802

The articulation of my Mikados was very stiff when I first acquired them and I thought that the stiffness could cause problems. I removed the chassis from the upper part of the loco and lubricated all of the pivot and sliding points. The front pivot is easy and may be lubricated without dismantling. The rear pivot is completely hidden. The center pivot, between the 2 motor blocks consists of a lower pivot that is easy to see and a similar upper pivot that can only be accessed by removing the chassis. The leading truck also needs lubricating where it slides across the fulcrum just to the left of the LGB sticker.

Now that the pivots are lubricated, with the loco upside-down the chassis flexes very easy without any 'stickiness'.

If your chassis is 'sticky' could that be adding to your problem? If the chassis is resisting articulation the center drivers may be pushing against the point blade?

Removing the chassis involves removing the front and rear trucks (not essential but less to handle), the front pivot screw and 2 screws at the rear where the chassis attaches to the pivot below (looking from underneath). There are 2 pairs of wires to the motor and a pair of plug-in connectors for sound trigger and chuff sensor.

Alan
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Thanks. I did look at the front truck and they do have springs. I may try and replace it with a stronger one for more down pressure. Articulations is ok.
 
I've posted a video on Youtube
that will show the switch sliding open as the 4th pair of drive wheels just clears the tongue.
 
Excellent video :clap:

So, to my simple mind, that switch blade moves beautifully smoothly ........................

There's nothing electrically or elctro-magnetically that's interfering with the switch (point) motor, is there ?

I mean, how can there be? But it moves so deliberately :mm::mm::mm:
 
Rhinochugger said:
Excellent video :clap:

So, to my simple mind, that switch blade moves beautifully smoothly ........................

There's nothing electrically or elctro-magnetically that's interfering with the switch (point) motor, is there ?

I mean, how can there be? But it moves so deliberately :mm::mm::mm:
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The only system change I’ve made is upgrading an LGB MTS power supply and controller to the Marklin CS3+.
 
pmindigo said:
I've posted a video on Youtube
that will show the switch sliding open as the 4th pair of drive wheels just clears the tongue.
Click to expand...
OK, now we have seen the problem 'live in action'
What I see, is a point blade moving when it shouldn't. That tells me that whatever is supposed to be stopping the blade moving, is not stopping the blade moving.
Now, there is no over centre spring like the manual LGB turnouts, so the 'stop' must be in the operating mechanism, somewhere, or perhaps in a sloppy linkage between the motor and the blades.
There could also be a problem with a vertical bow in the switchrail, and as weight is applied to the far end by the pivot at the frog, the pointy end lifts up, thus releasing any friction that may be hold the switch in place. Oh, running all this on carpet is only going to exacerbate any problems you have.
Try taking the whole point motor off, and the plastic between rail hump, set turnout, and hold position with cellotape. Run train, and see if there is any movement of the swith, either horozontal or vertical. If there is, then you have a trackage problem. If it is all OK, then you should look at the motor/linkage, but first try a manual throw, with spring in, to see if that works. If the whole thing works manual, either keep it that way, or repair/replace the electric mechanism.
 
pmindigo said:
I've posted a video on Youtube
that will show the switch sliding open as the 4th pair of drive wheels just clears the tongue.
Click to expand...
That is so odd. Ok another thought, have you tried moving the point motor to the other side of the track to see if the problem persists? May just change things.
 
AlanL said:
The reason that the point blades move is due to the 4th driver axle moving sideways as it nears the pivot point of the point blade.
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Great video it shows the 4 th driver moving sideways quite clearly. At the start of the clip the outside edge of the driver is on the rail head. It then moves suddenly towards the camera, taking the outside edge of the driver off the top of the rail head.It is this action that is moving the switch blades. The movement happens when the 4 th driver is 2 sleepers past the throw bar. At this position, the driver on the far side is just coming off the curved stock rail.

My tests showed that the groove for the traction tire is creating a step that is moving the 4 th driver axle sideways.
On the other side of the loco, the 4 th driver is riding on the curved stock rail and the groove for the traction tire has no effect. But as this driver travels, it falls off the curved stock rail and then the groove for the traction tire starts to be aligned between the rail head of the switch blade and the whole axle moves towards the camera taking the switch blade with it.

Why is it moving so much?

What condition are the traction tires?

What is the back to back dimension?

Is your point motor defective and not holding the blades?

On my tests, the blades only moved when the point motor was removed. They only opened 1 mm and didn't cause any problem.

Alan
 
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