Station start without the "hand of God"

[Playing trains with kids]

To me this is the biggest question for my layout, but I can't find any discussion anywhere:

 

How can you make sure a loco starts from a stop without requiring a push occasionally?

 

I have cleaned the wheels, the track, ensured it is not stopped on the plastic bit of the points etc.

It doesn't happen with every loco every time, but most locos occasionally.

Technical info: I have mostly Hornby/lima OO models from 1980s, the odd Wrenn loco (which interestingly, usually start without help), it is dc not dcc. I've even replaced one diesel with a CD can motor, but this doesn't always go without a push. I usually run the locos a bit first to give them a "warm up," but still have the problem......

 

My theory is that it's caused by the coils of the motor stopping in an awkward position, effectively stalling. Therefore my guess is that the only real solution is to use 5 pole motors (all mine are 3) or to install 2 motors (for diesels), one on each bogie; but before I invest in this, I'd like advice......

 

How has anyone else solved this problem? Or could someone point me to where this has been discussed (I'm sure it must have been, but I couldn't find it)?

 

Also, I noticed that when I send another loco down the same track to try and rescue the stopped loco, the stopped loco often comes to life well before the rescue loco comes near. I suspect this might be something to do with the back emf of the rescue loco doing something to the coils of the stopped loco? This makes me wonder if there is any way of simulating this to "boost" a stopped loco without physically putting the rescue loco on the track - although maybe here I'm moving into a more control topic than a motor topic?

 

 

Edited September 18, 2020 by Playing trains with kids
Added last para

[34theletterbetweenB&D]

1 hour ago, Playing trains with kids said:

To me this is the biggest question for my layout, but I can't find any discussion anywhere:

 

How can you make sure a loco starts from a stop without requiring a push occasionally?...

Welcome to the madhouse, and now brace yourself for a disappointing answer.

 

The reason it is not much discussed, is that this problem has now been fixed. Two methods are employed.

When RTR OO was equipped with low grade mechanisms, enthusiasts built their own to higher standards.

More recent RTR OO mechanisms are based on technique developed for HO models: the combination of high torque can motors, more efficient multistage gear trains and superior pick up arrangements is far more reliable.

 

The main problems with your 1980s Lima and Hornby are likely to be the relatively low torque of the pancake motors and the wobbly gear trains, combined with inefficient pick up on any driven wheels with traction tyres. (The best wheels for pick up are the driven wheels, putting a rubber insulator on any of them - a poor expedient to aid traction - now  largely abandoned in favour of weight which delivers both traction and higher contact pressure on the rail, a far better plan.) H-D and Wrenn wasn't perfect, but the weight on all metal tyred driven wheels was the asset then that it remains today.

 

I wouldn't spend a penny on improving the old, it is fundamentally limited. Buy the modern product when the cash is  available and you will notice the difference.

[ikcdab]

Well for what is worth. I don't think it's the motor stopping in the wrong place. Mainly because most locos have worm drive and pushing them a bit along the track doesn't rotate the motor.

Assuminf no physical blockages, if the loco won't start, there is only one possible  reason, no electrical continuity.

With starting, this can only be the wheel/rail interface which is very small. So it only needs a tiny speck of dust in the wrong place to stop things. 

If you keep the track very clean with something like IPA  (not a track rubber that can cause grooves that collect dirt) and keep loco wheels very clean too, things should be ok. Be it's a lot of frequent cleaning. A wagon with a pad soaked in IPA underneath run around can help  lot.

Rereading your post, I see that you have mostly Hornby/lima 1980s stock, this also won't help, with their "pancake" motors and split chassis which also collect dirt and need frequent cleaning. I see your wrenn engines are ok, they are far superior anyway which fits that theory. Try a modern Bachmann engine and see how that goes. You may well find it's just a feature on 1980s stock.

When you send the rescue loco, I suspect it's more the vibrations that jolt the stalled loco.

Ian

Edited September 18, 2020 by ikcdab

[Nearholmer]

Dirt in electrical contact points, not just wheel/rail, but wheel/pickup, motor brush/commutator etc.

 

Stiffness in old mechanisms.

 

Strip and scrupulously clean everything, reassemble, oil bearings very lightly, and grease gears very sparingly, both using modern synthetics.

 

Then things will run as well as they ever did, which still won’t be as good as modern mechanisms, but at least they should self-start 99% of the time.

 

Triang X04 type motors will sometimes stick in a ‘cogged’ position, even when everything is ‘perfect’. The way to get them to stick is to increase the voltage very slowly, hoping for a smooth, gentle start. The gentle increase fails to give a pulse of torque to overcome static friction in the mechanism. If You increase voltage quickly, you will get a “jack rabbit” start, which isn’t what you want, but at least it starts! Because of the very high gearing, Nellie is particularly prone to this.

[Michael Hodgson]

The problem is almost always the pickups, there often weren't enough of them, and I think there can also be poor contact with loco brushes/commutator. 

 

If you want to reduce the problem of poor rail contact with older style mechanisms. one of of doing it is to double-head your trains.  If one engine stops on a bit of dirt and the other doesn't, the good one will start and effective act as the "hand of God".

 

Another solution to the problem I have seen in the past was a mallet pivoted under the baseboard attached to an operating handle by a rope to give it a bash from below!

[Playing trains with kids]

Thanks for the swift responses, I had not realised this was now an old problem! I'm sure I've seen the hand method once or twice on an exhibition, but maybe it was because like me they're still attached to their childhood rolling stock.

 

I admit I came back to the hobby after about 20 years away, unpacked the old stuff and was surprised that so much still worked. A lot of things have passed me by and I'm still catching up. The idea of double heading sounds the most practical at the moment, but I do like the mallet idea.

 

I haven't yet used cleaning fluid/IPA; I live abroad and I haven't yet found it where I live, and you can't transport it by air

 

So if the problem is conductivity, then adding a second motor won't help any more than increasing the pickup. But if the problem is torque/stall, then a second motor bogie would potentially help. But doubling heading would help either way.

 

At the moment my kids are quite young so the rolling stock has to be easily (cheaply) replaceable so I'm not about to invest in modern stock. However, at least when they're around there's plenty of hands to push the locos! Just the problem of when I'm playing trains when they're in bed!

[Pandora]

Buy a low cost digital volmeter/ampmeter from ebay or the supermarket such as Lidl/Aldi, when wired up to disp[aly current,  you tell see if the loco has stalled from non-continuity of pickups, ( zero current flow  or a stalled motor, curent flowing

[Phil Bullock]

1 hour ago, Michael Hodgson said:

The problem is almost always the pickups, there often weren't enough of them, and I think there can also be poor contact with loco brushes/commutator. 

 

If you want to reduce the problem of poor rail contact with older style mechanisms. one of of doing it is to double-head your trains.  If one engine stops on a bit of dirt and the other doesn't, the good one will start and effective act as the "hand of God".

 

Another solution to the problem I have seen in the past was a mallet pivoted under the baseboard attached to an operating handle by a rope to give it a bash from below!

A device designed to produce low frequency vibrations is a bit more subtle and less likely to cause derailments

[Playing trains with kids]

and obviously, I forgot to add I need to do lots of cleaning/servicing!

Thanks for the great tips everyone! Will try the ammeter test, just need to think about how to wire it in, I have a multimeter.  Although by Murphy's law I probably won't have the problem for a while when I'm looking for it.

 

I had the idea of installing something more subtle to vibrate the board, any one done this? One component I've seen available is a mobile phone vibrator, although the challenge is to fix it to the board without dampening the vibrations (my board is plywood). N.B. choose your words carefully if you do an internet search for this......

Edited September 18, 2020 by Playing trains with kids

[kipford]

Assuming you have access to shops, get hold of a can of lighter fluid (it contains Naptha and leaves less residue than IPA) and use that to clean both the track and the wheels.  By  way ensure you not only clean the loco wheels  but also rolling stock wheels as the plastic wheels on wagons pick and deposit dirt very effectively.

[Theakerr]

Back in the day a lot of people, including me, installed a RELCO unit to keep the tracks clean.  I'm not really sure how effective they were at keeping the tracks clean but in my opinion it sure improved the starting of some of those old locos.   I'm not sure if they are still made, but Hornby did do something similar and they do come up second hand.  Ironically over the last year I have sold as part of estate sales 5 of them for Can$5.00 and they have gone almost as soon as they were listed.

[Legend]

I run modern stock but I also have the heritage fleet that date back to the 60s , so I’ve got Tri-ang,, Hornby , Lima , Mainline, Airfix, Wrenn , Bachmann, Dapol  all in the fleet. It’s certainly true that sometimes the older locos need a bit of a nudge but not exclusively . I have a 1971 B12 for instance that moves off quite easily . The key is as other have said cleaning track and wheels as well as lubrication .  Even pancake or Ringfield motors should be ok . However I gave two other suggestions . What track are you using?  I find that modern nickel silver track is much better than old Hornby steel track, so could the age of your track be an issue?  The other thing I use is an electronic track cleaner. Some will react with horror to this . It’s not compatible with DCC chipped locos or coreless motors (I think) but it works for me . I find I don’t really need to clean track much at all , although I have a track cleaning rubber, but I do keep the wheels of my locos clean with a Gaugemaster fibre pen 
 

Hope this is of help 

[Wheatley]

Hornby and Lima deisels of the period only pick up on one side of each bogie. On Hornby locos the current path is via the steel axles and mazak bogie casting via a layer of whatever it was last lubricated with, on Lima a sprung wiper runs on each axle.

 

Hornby steam locos of similar age generally pick up via the loco wheels on one side, again via the axles and mazak loco chassis, and via the axles/tender chassis on the other side. Same steel/mazak/crud interface.

 

Lima steam locos, well I only ever bought one (Crab) and pick ups were the least of its reliability issues. 

 

In all cases only half the wheels (at best) are conducting electricity. If you can rig up some pick ups on the other wheels you massively decrease the opportunities for nothing to be picking up !

 

I'm with ikcdab - vibration is more likely to be causing the sudden resurrection than stray wiggly amps. 

Edited September 18, 2020 by Wheatley

[PatB]

The late John Allison, on his 7mm minimum space layouts, employed a device he christened the Seismopump, which was a variation on the under-baseboard mallet. IIRC it was a vertical plunger operating a lever with a striker on the other end. I suspect that careful selection of lever length, travel and striker weight could arrive at a solution that would deliver sufficient knock without derailing everything. 

[DCB]

Some old controllers had a boost button to give a full 12 volts to jolt a train into motion.   A lot of my locos don't like starting as they were built from second hand parts 30 years ago with 3 pole X04 motors but backing up slightly helps.   Clean rails help but clean the inside corners where the wheels run not the tops.

Under bad dirty rail conditions weight on the pick up wheels is crucial.  My Bachmann Pannier with 6 wheel pick wont keep going where a Cast Metal body Farish Pannier with Triang chassis with half as much weight again and only 4 wheel pick up splashes along happily, did I mention I run in the rain on the garden branch...

[Playing trains with kids]

Thanks again everyone, some helpful tips. I haven't yet been able to rig it up with the ammeter to check, but from observation it does seem like 90% of the time it is due to electrical contact, with the occasional stall (noted either by humming, or by the loco making a small jolt then stopping).

 

I've got hold of some lighter fluid so will get to work with cleaning.

 

I have a question: as mentioned, the axle-chassis conduction path on the diesels, any advice as to what this should be cleaned/lubricated with?

 

I have also ordered some components to make a "Seismic effect" so we'll see if that also helps.

 

I do have an old relco unit which was close to being chucked because I was under the impression they are no longer considered useful. It probably won't help as I use controllers that give 12v pulses (PWM), and I'm not sure how the unit would be compatible. I will also look into adding extra weight, I had noticed this problem on the Hornby Class 43 and added extra weight to the non-powered bogie as there was intermittent pickup as it went around; sounds like I need to do this to other locos too.

 

[melmerby]

On 18/09/2020 at 09:09, ikcdab said:

Rereading your post, I see that you have mostly Hornby/lima 1980s stock, this also won't help, with their "pancake" motors and split chassis which also collect dirt and need frequent cleaning.

No Hornby loco AFAIK ever has had a split chassis and I don't think Lima did either

[Dave John]

The seismic effect works for me. 

 

 

 

[Free At Last]

God's hand has been idle on my railway since I used graphite on the rails. 

Not suffered a non-starter or a stutterer since reading the post on graphite treatment and purchasing and using a 9B stick. According to some it is the work of the devil but I am now a follower of this black magic.

[kevinlms]

6 hours ago, Free At Last said:

God's hand has been idle on my railway since I used graphite on the rails. 

Not suffered a non-starter or a stutterer since reading the post on graphite treatment and purchasing and using a 9B stick. According to some it is the work of the devil but I am now a follower of this black magic.

Grey magic!

 

Glad to hear it still works. 

[andyman7]

For what it's worth, despite the derision in some quarters for the old Lima/Hornby Ringfield mechanisms, if you do fit extra pickup and extra weight they can run beautifully with virtually zero stalling.

[kevinlms]

8 hours ago, andyman7 said:

For what it's worth, despite the derision in some quarters for the old Lima/Hornby Ringfield mechanisms, if you do fit extra pickup and extra weight they can run beautifully with virtually zero stalling.

Which of course raises the question as to why Hornby and Lima churned out models with the same fault for 30 years.

[BR60103]

I use Peco Electrolube on various contacts.  Aside: I was going to use it on the pickups for some coach lighting. I'd done about a half dozen of them and saw that the lights weren't on at all. Then I noticed that the tube I'd used was actually lubricating oil. I had to carefully towel them all off and use real Electrolube. That made a lot of difference.

I'd use Elube for any spots where the pickup goes through the axle ends into bogie sideframes or through axles into the mainframes.

Older motors had a characteristic called "JackRabbit start".  The motor needed more volts to start than to run at minimum speed. There was a feature in power packs called "pulse power" which was half wave DC  where only half the AC was rectified. This was supposed to act like a lot of little blows on the motor to get it spinning. The pulse was supposed to be turned off after a point because it made the motor heat up.

 

[PatB]

2 hours ago, kevinlms said:

Which of course raises the question as to why Hornby and Lima churned out models with the same fault for 30 years.

Because people still bought them, there being little alternative. 

[Playing trains with kids]

PS I love the expression "heritage fleet."