COUPLINGS, COWCATCHERS AND PICKUPS


Couplings, cowcatchers and pickups


doing it properly - one of Bob Barnard's locos fitted with Meridian couplings

It has been said that the overhangs on L&B Manning Wardles are actually greater than my stomach's. This does mean that there are some serious difficulties in navigating fixed couplings around the rather standard 12" radius curves of the 009 layout. The purist will still go with scale couplings, which can be purchased from Meridian Models. The problem is actually using them. Reaching over a layout with a pointy stick and a shaky hand to lift up chopper couplings is not everyone's idea of fun.

At County Gate, we have opted for the Greenwich couplings, which look a bit like narrow gauge ones and offer automatic coupling and uncoupling with magnets hidden between the rails.

There are a number of ways to make these work. I shall first describe the method we use on our Backwoods MWs.


click image to enlarge

The front coupling does not have a lifting loop and therefore, the cowcatcher can remain intact. We just extend the buffer beam slot a little to allow for movement.  We use fine steel wire. Form a loop at one end and where best, bend a crank to bring the coupling to the correct height. The Greenwich Coupling is cut short and soldered to the end of the wire. Easy peasy.

The rear is a tad more demanding.


click image to enlarge

We first have to solder a nut to the chassis to take the fixing screw. Don't forget that the trick to solder nuts without getting solder into the threads is to jam a cocktail stick down the nut! The lifting loop of the Greenwich does need a lot of room, and we are forced to remove the centre of the cowcatcher as shown.  The system does work very well although care has to be taken not to bend them during handling. The spring of the wire offers the perfect 'give' around corners.

The only loco that we are able to use fixed couplings with is the Garratt which is articulated and with minimal overhangs.

Some locos do not offer a long enough length of empty chassis to accommodate a spring wire. A case in point would be the recently built 'Mad Mallet'. 


A cruciform wire is soldered to the coupling which retains two Bemo coupling springs. There you have it, a perfect sprung coupling.

Here, the coupling is placed on a wire pivot. It is retained in placed with a small washer. Two small sheets of brass are soldered to the rear of the buffer beam to make the coupling box. In some cases, the box would be formed by the existing chassis fitted to the loco.

Another method I use is good for loco couplings.

 

the trouble with Lyn


this was enough to derail the following car

In an ideal world, one would use scale radii on turnouts. Sadly, if this had been done at County Gate, we would never have fitted everything in.

Now the worst offender for coupling lock is our Baldwin 'Lyn' whose overhangs exceed even those of Jordan.

We now use a very fine spring wire which slides in a small hole in a bracket soldered onto the cross member just aft of the rear driver to centralise the coupling. This immensely improves the situation but at a couple of tight double reverse curves Lyn was still pulling the following car off the track. Our trains are intended to be fixed consists, so we have been able to modify the coupling of the adjacent bogie van.

 


new 'Lyn' coupling arrangement - click image to enlarge

The van coupling is free pivoting under the bogie and centralised by a long spring wire
 

coupling height

The coupling height of our rolling stock goes back to the locomotives made by me in the early 1970s. For us it was 5.5mm to the top of the buffer plate. It seems that this has subsequently become a bit of a standard height, but no thanks to me! I have a short section of track glued onto foam card with a 'buffer' glued to one end. Into the buffer is glued a Greenwich coupler at the correct height.  All stock is visually checked against this.


 

electrical pickups

The Backwoods instructions suggest that the electrical pickup be made using the phosphor bronze wire supplied contacting the wheel treads. This is in principle a very bad methodology because dirt picked up from the rails will gradually diminish conductivity. Our chassis builder, Peter Wallace developed a different method.


click image to enlarge

With space at a premium he solved the problem by having one sprung wire contacting the flange, while the other wheels had power picked up from the rear of the rims using spring plungers. Sadly, after many hours running, the plungers began to fail and have since been replaced with phosphor bronze sprung wire pickups acting on the back of the wheels.
 

how is the electricity collected from the wheels?

Without question, the worst place to collect the power is through contacts acting on the wheel treads. Dirt will inevitably collect on the treads and transfer to the collectors with the result that sooner, rather than later, the loco will stall. Far better to collect the power from contacts acting on the wheel rims or back of the wheels. Sprung collectors are usual but very small plunger collectors are available and are excellent.

Most modern chassis have insulated driving wheels on one side only while the entire chassis is live with the opposite polarity. This is now standard practice with say, Backwoods chassis. This can have its drawbacks too. Great care is needed to make sure that pony truck wheels can never touch the chassis.

Worse, some methods of installing couplings means that they are live to the chassis. Unless you get it right, double heading can cause a dead short. This means that you must always set up your loco with a common polarity and never turn them around.

Another solution is the 'split chassis' system. Here, the current is transferred through the axleboxes but there are problems when scratch building to prevent the 'wrong bits of the loco touching live bits' and thus shorting out. The axles of a full split chassis system must also have an electrical break in the middle of the axles. Thank goodness for Plasticard and epoxy glues!

The advantage of the split chassis is that there is no resistance due to collectors acting on the wheels. The spacers between the chassis frames also have to be insulating. The drawing below is how I built the chassis for my K1 Garratt. For this type of chassis, I use a conducting lubricant.


this Manning Wardle chassis has a 'live' side and plunger pickups on the other


re-engineered Backwoods Baldwin chassis

One advantage of DC operation is that electronic track cleaners can be employed. Quite often, a small resistance between the wheels and rail are blown away with a micro jolt of high voltage (they are also quite good for keeping your cat off the track).

If you are running DCC, you can programme an additional start current which can often help.

Some products can be used on the track such a Rail Zip or indeed a soft woodworking pencil. There can be wheel slipping on gradients using some of these products.
 

flywheels

If at all possible, flywheels should be built into the model. Their size is going to be small to fit in the average 009 body but is often sufficient to help with smooth running and help the loco through dead spots. Sadly, space just cannot be found in all locos, such as in the Backwoods 'Lyn' shown above.
 

gearing

We all expect good slow running these days. This will mean a gear train with accurate meshing of gears and good bearings are an essential part of the formula. Some Backwood kits have the motor worm drive slightly offset. While this may work, I have found that excessive wear can take place.
 

maintenance and wear

Some specialist chassis are constructed in such a way that it is almost impossible to take them apart to effect repairs. The standard Backwoods chassis are exceptionally difficult for instance. If at all possible, assume that everything will eventually wear out and need replacing.

Some chassis designs are simply asking to wear out due to their construction.

Firstly, let's look at the much vaunted expensive Roco outside frame chassis.


click on image to enlarge


the Roco 'rip-off'

Here, the axles are not in bushes but make point contact with the die cast chassis. Very quickly there is wear and the loco will no longer run properly. The plastic keeper plate also slowly wears down.  On top of all this, the Mashima motors supplied in the loco very quickly develop a very rough spot when slow running. This is another thing to look out for. These days, if at all possible, I remove motors and run them light. In my view, there just should not be any rough spots at all.

For reliable running, axles must be fitted in proper bushes in brass or better still, bronze.


a properly bushed chassis by Victors Models (Sandy River No 19)

Equally, coupling rods and crank pins will wear. This is particularly the case with chassis that are driven through one axle as is the case with the chassis shown above. I now favour hard steel crank pins and bronze bushes sweated into the coupling rods. If you think this is a tad over the top, our first Backwoods Manning Wardle wore out its crank pins and rods after 20 hours of operation.

This leads us on to the next issue. If only one axle is driven, it is far far better to drive the centre axle in a six coupled unit rather than an end one, as shown above. There is far less binding and likelihood of wear. In my view, the best solution is to drive all coupled wheels.

The Early Lilliput chassis did this and will run forever given simple maintenance. True, they run too fast and the motor is not the best but the coupling rods do not do any work so they can be reduced to scale size with no concerns. My Baldwin, which has such a chassis and is fitted with scale sized rods, ran 24/7 for a year in a shop window. It still runs great now!


early Lilliput chassis

One chassis which potentially fulfils all the requirements is the new N Drive Productions unit. They even promise to offer them with outside frames. True, no valve gear comes with it, but this is easy enough to add, using a fret available from Backwoods Miniatures at 18. The drawback is that at present, their construction is a part time job and as they become more popular there might be some delivery delay. Hopefully he will find ways of increasing production.


N Drive Productions 6 coupled outside frame chassis


0-4-0 chassis by
N Drive Productions (42)

testing

I have always tested my chassis for 8 hours running forwards and a further eight backwards, If any sign of wear showed after this ordeal, the design would be re-engineered. That is, until I bought the Roco chassis, which I assumed had been previously rigorously tested. How wrong I was and the whole exercise has cost me hours of work and 400!

By the way, it is worth keeping logbooks for your locos so you can record the hours they have run.
 

changing perspective

There are, of course, those who just like to collect locos...lots of them. But for those who are building a layout and want their locos to look as good as possible, is it not time to take a long hard look at the quality of running chassis? Costs are coming down but there is no doubt that 'proper' locos are going to be more expensive. What would you rather have, numerous toy trains or fewer proper models?
 

bogies and wheels

I have got thoroughly fed up with 009 bogies and wheels supplied in kits. They are not very free running, often inaccurate and if one is able to get them working, they can be very delicate.

Mass produced N gauge equipment is, on the other hand, very reliable. Simple solution...use N gauge gear. Our Lynton and Barnstaple narrow gauge rolling stock sits on the rails rather like sausage dogs - you really can't see the undercarriage! I hear anguished purists bemoaning the use of such gear, but they are often same folks who spend a lot of their time putting things back on the rails!

I have selected bogies produced by Green Max. These are getting hard to find these days but are still available if you Googler for them. We use DT 22 bogies for goods and DT 16 for coaching stock (or equivalents). The wheel bases are a bit shorter, which allows one to place the bogies between the frames, where they are supposed to be, and still get sufficient movement for 12" radius turnouts. At present, there seems to be supply difficulties with Greenmax.

I have rarely found a Green Max wheel out of 'back to back' but I do check every one with a gauge. The additional advantage of Greenmax wheels is that only one wheel is insulated so they can also be used for current collection. I just pull out the knuckle coupling and glue in a Greenwich version.


Green Max goods bogie

 

getting power to the locos

Many of our locos have small wheels and not enough of them to be able to reliably collect current at all time to run. In order to get more wheels to supply current, pony wheels can be used as well as the drivers. The simplest method is to use just one wheel each pony truck. With Greenmax wheels, this is simple.


 

companion cars

Another method is to use the adjacent wagon/coach as a current collector. Often, locos remain in a fixed consist so under these circumstances this is a very good option. All our main line trains that run under automation are connected to companion cars and they almost never stall. We stick copper tape on the inside of one bogie side (opposite side for the other bogie) and link up with thin flexible multistrand wire to connectors to the loco. A dap of Copperslip grease in the bearing hole will ensure good electrical contact.


self adhesive copper tape attached to one side of a bogie. The pickup wire can be seen.

The connectors used are supplied by Express models. Another advantage is that is is very easy to test a loco on DCC by just plugging in with a lead.

Once you have soldered on the correct wires, you will need to encase the joint in epoxy, otherwise the joint will break in time.

The choice of wire as connectors is difficult. They do have to be very soft and flexible. The best is that supplied by DCC Supplies. They use it for DCC chips.

The plugs are inserted with tweezers and are marked with a small spot of paint to ensure correct polarity.


micro connectors supplied by Express Models


'Lyn' and her best friend!
 

lazy locos

I always advocate using 'companion cars' connected to locos that run with fixed consists. The additional current collection makes these trains almost 100% reliable. The problem at times is that the bogies of the companion car are far better at collecting current than the rigid chassis of the locos themselves. After a period of operation, the locos become very reluctant to operate on their own. Careful cleaning is needed and after a little coaxing, they will begin to run again. I always let them travel a few circuits in both directions on their own before reattaching to the companion car.

 

some problems

Despite best efforts, occasionally we find a piece of rolling stock that just will not stay on the rails.

  • Check back to back measurements on all wheels

  • Is there a lump of say, glue, attached to a wheel tread?

  • Are the couplings sticking against the body or not giving sufficient movement side to side where there are derailments?

  • If bogies, is there enough room for them to move sufficiently?

  • Is the stock heavy enough?

  • Are the wheel sets/bogies in line? Check the vehicle on a sheet of glass

If none of these things work sell the railway!