Solving the Points Running Problem

[Fishmanoz]

I've seen lots of people talking about the problems with running particularly 0-4-0 and 0-6-0 locos over point frogs but does anyone have a solution?

 

For the purposes of this thread, can we assume that the rails and wheels are clean and the pickups

 

are tensioned against the wheels, then concentrate on what problems might remain and how to fix them.

 

If I can illustrate the problem from my own experience - I have 2 Collector locos; one runs perfectly, the other always stops when a frog is under

 

the right rear wheel, showing that there is no electrical contact from the right front wheel. But everything is clean and the pickup is in contact with the wheel. What can be wrong and how do I find and fix it?

 

I also have 2 0-6-0 locos (Mixed Freight

 

so Railroad standard). One just runs like a dog, jerky all the time at low speed but it doesn't stop on points - I'm assuming this is just general bad contact but I'm not worried about this one because it's going back as it also has a faulty decoder (yes,

 

I'm running DCC) which won't operate in reverse. More puzzling is the other 0-6-0. It usually (but not quite always) stops when the left middle wheel is on a frog, then it often restarts (not always) and sometimes stops again immediately when the left rear

 

wheel is on the same frog. As far as I can tell, there must be bad contact between the wheel/s and pickup only at particular areas on the wheel, but I certainly can't see that area and polishing has got me nowhere so far. Any thoughts on that one?

 

By

 

the way, my Flying Scotsman Railroad works fine, I'm happy with that one.

 

And a final question - am I likely to have the same problems with other 0-6-0s such as the Terrier class which I'm thinking of getting?

[oorail]

Are you using Hornby insulfrog points? It sounds like you might be (slow speed, loco stopping on the frog due to no electrical contact). The problem sounds like the plastic insulated frog is too large for your 0-6-0 loco.

 

Since you are running

 

DCC and don't need the isolation, one possible fix is to make the plastic insulated frog conduct. One way to do this is with "magnetic blackboard paint". I'm not sure if they sell it in the UK, but here in the USA they sell spray cans of whats called "magnetic

 

chalkboard paint". This is a type of paint that you can spray on your wall to let kids use a section of your wall as a blackboard. Its not really magnetic, but contains small pieces of iron filings inside the paint. They market it as "magnetic" because the

 

iron filings allow kids to stick those letters with the little magnets in them to the wall.

 

To make it work you need to do this:

 

1. Buy a good quality magnetic blackboard paint (ideally black, grey or brown)

2. Spray it into a small container

 

(plastic bottle tops are good)

3. Take a paint brush and apply it to something plastic (spare sleeper from flex track works)

4. Let it dry, and repeat for at least 3 coats

5. Using a continuity tester on a multimeter to check that its now conductive

6.

 

Check the resistance isn't too high with the multimeter

 

I went through four different brands of paint before I found one that would conduct well enough, luckily I have small kids, so we had the paint laying around :)

 

Its more expensive, but there

 

are a few companies selling electrically conductive paint but I haven't tested it.

 

Once you found something that works, apply a small amount of it to the frog on the insulfrog points (essentially making the plastic piece that doesn't conduct smaller).

 

Until the loco no longer stalls across the points at slow speed.

 

Hope that helps

[Western Fan]

Sorry 00rail77 but I can’t agree that the problem is the length of the dead section. I acknowledge immediately that it might be me that’s wrong and I want to talk it through respectfully, not start a squabble.

This is my take. In order to work the motor

 

needs a constant supply of current. Electrical engineers like nice tight connections but they can’t have them on a model locomotive as it has to move. Given that a very weak electrical supply has to find a path through a moving point contact (the wheel) and

 

a lightly sprung connection (the pickups) I sometimes find it surprising that the models ever move at all. The problem is compounded because the axles slide from side to side within the chassis. The pressure on the pickups vary with a tendency to lose contact

 

altogether in certain position. The locomotives only need one working pickup but as all of the pickups are inherently unreliable it is desirable to compensate by increasing the number of pickups, so that the locomotive does not need each pickup to work every

 

time. This is not a problem on larger engines but hard to achieve on 4 wheelers (many 0-6-0s only have 4 wheels that can be used to pickup current). The problem is compounded by dead frog points. Although very useful in other ways they mean that one of the

 

pickups on the locomotive cannot work as a wheel passes through it. Shortening the dead section reduces the gap but there needs to be a dead section when the 0-4-0 will depend entirely on one pickup to work. Reducing the dead section might hide the problem

 

by giving the locomotive a shorter section through which to slide but it cannot cure the fault. I think your problem is that the single pick up does not work either at all or, more likely, because the axle slides in the chassis. If this is the problem then

 

the answer is in retensioning the pickups.

There is another possibility. The tight curve induced by the point increases the resistance to the locomotive moving. This could be exaggerated if the wheels are not quite parallel on the axle or the quartering

 

is slightly out. Maybe there is tight spot. A controller or chip that monitors the back EMF and compensates automatically (lots do) could fix.

Or of course you could go back to the Hornby Dublo three rail system that had live frog points and did not depend

 

on lightly sprung electrical pickups on the back of wheels (just being mischievous now!)

 

[oorail]

Western Fan, I agree with you that the root cause of the problem is more than likely a dodgy set of pickups. The solution I posted above does work, and can save some hassle, here is why...

 

If you look at a set of regular Hornby insulfrog points

 

there is the plastic V and just ahead of the base of the V there are two plastic sections about 2mm or so in length on either rail. Opposite it there is a plastic rail. If you look at that section very carefully as a slow moving locomotive traverses it, some

 

locomotives will have a wheel "dip" as it exits the V. Depending on the locomotive and how slow it is moving, that wheel will end up touching the plastic base of the V, and the 2mm plastic piece on the rail at the base of the V. If the pickup on the other

 

wheel isn't great, then it will stop. It can though dip enough (especially at slow speeds) that the other wheel with pickups is raised enough off the track and it just stops.

 

Painting the inside of the rail and then shortening the V (or shortening

 

the 2mm plastic piece) allows that first wheel to remain powered even at slow speeds. It also solves the problem when some locomotives stutter across the points at slow speeds as well.

[morairamike]

I have a problem with an 08 shunter. The railroad onenwhich was converted by a shop before it was given to me. This will not run thru points. A Thomas that I have will, changing the chassis over makes the 08 work, (all hornby set track insul frog using

 

DCC)

Long investigation of the problem highlighted the following.

 

1) All the contacts are in contact with the wheeels when on the track. Have been adjusted to stay in contact with axles at full excursion to left and right.

 

2) All capacitors

 

removed from locos

 

3) and here is the problem, the front set of wheels are not in contact with the track when the 08 stops, this is due to a slight distortion in the chassis. As the loco goes over the gap between the switched rail and the frog it rocks

 

and lifts the wheel off the track sufficiently to break contact.

 

As a cure I am going to buy and use stay alive decoders.

 

[markSandD]

It is not always the loco chassis that is at fault, several issues can make a loco stall on insulfrog points and crossings, the problems are made worse with DCC control:

 

1: Points need to be laid as level as possible, It is worth your time using

 

the edge of a steel ruler to make sure that the rails are level all the way across the point/crossing, if the point is not level, a small locomotive with limited electrical pickup such as an 0-4-0 or 0-6-0 can have 1 or more of its wheels slighly lifted off

 

the track causing loss of electrical contact.

 

2: Clean rail and loco wheel treads are a must.

 

3: Make sure the rail joiners are tight.

 

4: Check the wiper pickups on the loco chassis, even down to cleaning the back of the loco wheels (where

 

the wiper pickup bears on the wheel).

 

5: It it is a 'tender drive' model, make sure the loco runs freely, and that the wheels are quartered correctly and not causing the loco to lift 1 or more of its wheels off the track as they rotate (I had this problem

 

recently). Also make sure that the connections between loco and tender are sound.

 

6: Diamond crossings cause momentary shorting problems, which under DC control would not cause a problem, other than a spark, can cause a DCC unit to trip out.

[Western Fan]

Thanks for the courtesy of a detailed explanation 00rail 77. Why not try itFishmanoz and tell us how you get on? You don’t have much to lose.

[Fishmanoz]

Thanks everyone for the suggestions and, Western Fan, for the encouragement to try oorail77's. I must admit I didn't like this suggestion greatly as the frog is there to insulate, or you get a short across the rails as the straight track crosses over the

 

turnout track - doesn't mean it couldn't be smaller though.

 

But my first experiment just now was to check for track contact on the front wheels as the rear wheel was on the frog and guess what - no contact. I believe this is morairamike's problem -

 

twisted chassis - rather than 00rail77's dip at the point of the vee because it happens at the other end of the vee initially and continues right along it. And it was possible to make it restart by twisting or pushing from the top over the front axle.

 

I'll

 

have to do some more experimenting with the 0-6-0, especially the fact that it stops with each of 2 axles on the frog (goes again between) as I can't figure the non-contact logic for this.

 

And I'm still wondering about buying better quality 0-6-0s (Terrier)

 

and whether I'll get the same problem again. Any thoughts on this anyone?

[Sandbar]

I had another brand of 0-4-0 loco (not Hornby) which had problems. It turned out that the pickups seemed to be made from poor conductive material. It sort of worked for a while when new. After trying to find and fix, it was by accident that I decided to test the pick ups with a multimeter and found the fault. New pickup was fitted and now there is no problem.

It was probably the one in a million problem, but it can happen.

You will notice that everything works perfectly until you have a visitor then problems happen!

[BagEndJct]

I had my 0-6-0 diesel shunter fitted with proper "stay alive" capacitors (which also meant the cost of a new DCC decoder) by http://www.oliviastrains.com/

 

It was NOT cheap (send them the details and they'll give you a price) but worth it for me as it just keeps running, without a pause, over all my track and points. I'm "saving up" to have another of my 0-6-0s done. I have one which has a blown decoder so it will be killing two birds with one (or more) chips!

[96RAF]

My problem with a Bacchmann Jinty 0-6-0 over points was the spring detailing under the chassis caused the loco to rock and lift a wheel which rendered it marooned on the plastic.

 

My solution, which may not suit some people, was to apply a rough file to the springs to regain clearance.

 

There was discussion on another forum about using conductive paint over the plastic frog and the consensus was - dont do it for fear of a invoking a short.

 

The only true way to fix the insulated frog gap problem is to use a conducting frog and proper cross switch wiring actuated by the point movement.

 

Like this...

In case its not clear from the diagram - when the point changes to branch route so does the switch change over to apply the opposite (red) potential to the frog.

/media/tinymce_upload/a502891be8123c5bb100de74297c4e59.PNG

 

Oddly my 0-4-0 Collectors Club models traverse Hornby points OK even at modest speeds. I have more problems with Pacifics causing shorts over points than anything else.

Rob 

[NormanQ4]

Much water has gone under the bridge since Fishy set this train running on 10 March 2012.

I wonder if he remembers writing this post.

[RDS]

I fixed my 'slow running over points problem' using advice from WTD (walkingthedog) after he recommended adding another track fastening pin in the centre of the points.  I had always thought that my points were flat but this simple fix worked perfectly.  Drill the sleeper at the centre of the point with a 1.2mm drill first.

[walkingthedog]

I give that advice so often I'm beginning to think I should publish it as a book.  😆

[RDS]

@WTD

.. and with the number of times I think I have mentioned on here, I could probably donate a chapter for you.

[walkingthedog]

Let's do it RDS, could get a bit boring  😆

[2e0dtoeric]

Something that nobody else has mentioned on this particular thread, but is a well-known problem. Insulfrog points are now known to have the plastic 'vee' moulded a bit too shallow, (worn pattern?) so as a wheel runs onto it, the flange bottoms out, and lifts the whole axle up a half milli or so, breaking the connection to the metal track of the following wheels.

The solution is to file the slot a little bit deeper.

[RDS]

... The solution is to file the slot a little bit deeper.

 

I have done that as well but the extra pin was more successful for me

[96RAF]

Here is what we are talking about...

...quite why that elevated ramp has to be that height either side of the Vee I do not know. Common sense would indicate a groove down to sleeper top height.

/media/tinymce_upload/4ce2ce136104ea9b5870bdeefb8c48a8.JPG

[NormanQ4]

I find it interesting that some of you have found the slot to be too shallow.

I had the exact opposite problem with some express points where the slot was too deep.

On these the gap that has to be bridged is 12mm and the racket that the big driving wheels made when they dropped into it as they passed over was driving me nuts.

I had to cut a triangular piece of thin plastic card and stick it in the bottom so that in this area the loco was actually running on the wheel flanges for 12mm.

By pure chance the plastic card was just the right thickness and there was no break in the power supply to the loco.

[walkingthedog]

Norman I used to have a set of points that certain locos fell in to. If the right front wheel went down the rear left one came up, wierd.  I did the same as you, worked a treat. 

[Les paul]

After reading all these comments, it almost feels like most of you are using a sledge hammer to crack a nut.  If you have a train with stop start running problems over any area be it points or track, if possible run a train of the same type over the same area and see if the same thing happens. If not you know its the loco. If its track then you clean it. or with points make sure where the switch rails meet that the connections are clean. This will invariably solve the problem. I run loads of different locomotives in DCC and DC mode over insulfrog points and have no problems whatsoever.  As someone said earlier power pickups are most likely the problem, especially if the track is clean or points are closing correctly. I bought a Terrier class R3528 which stoppped on points.  Not having another I put two Hattons P class locos around the track and they ran fine. So I simply pulled the bottom of the train chassis off ( 8 screws ), pushed the 4 brass looking pickups in and out a few times, made sure they were seated on the wheels correctly and Hey Presto, job done. I assume one of the sprung brass pick ups was stuck or sticking, dust, dirt who knows.  Here is a video showing the loco playing up and after running nice.

Regards

[walkingthedog]

What you have said is pretty standard practice to those with a bit of experience. Newcomers might not have a clue  😆

 

As this post is fairly old hopefully the OP is now experienced.  😉

[morairamike]

I appreciate the thread us old but it was brought back to life. Yep at Halton for my sins, lived there before joining up Wendover John Colet school boy. That's 60 years ago. The 100 year lease runs out 2020 then it's gone. Supposedly being built on but who knows for sure. In 100 years it will a different world yet again and by modern science I'll be 174 and still playing trains. Ho hum just another day in paradise.

[Sailbadthesinner]

In the long standing tradition of resurrecting this thread, I have the following observations that might help:

Several of my locomotives 0-4-0 and 0-6-0 types ranging from brand new to 46 years old have a problem crossing Hornby points at low speed.

The problem is not with the loco, it's wheels or pickups it is simply that the slot in the insulated frog section of the points is too shallow (as has been observed by other in this thread).  It lifts one wheel and tilts the loco so the other wheel on the same side loses contact.  I can even rock the loco back and forth once it is stranded on the frog and see the wheels lifting.

I measured various new Hornby points and the slot varies from 1.08 to 1.14mm deep.The flange on various Hornby locos that have a problem are 1.32 to 1.40mm.I measured the flanges on some non Hornby locos that work fine and they are 0.74 to 1.20mm.The slots on some 40+ year old Hornby points are 1.89 to 1.98mm deep.  

The solution (previously mentioned) is to file the slots deeper (or buy non Hornby points).

Why are Hornby now selling products that aren't compatible with their own locos??