I've just acquired one of the older GF Coronation Pacifics as I'm modelling the West Coast main line circa 1955-65. My Duchess runs very well. The motor drives the loco's main wheels but I understand some newer locos are tender driven. Apart from allowing more accurate detailing in some respects, does anyone have opinions on the relative performance of the two drive types? My Duchess seems a reasonable "puller" but how do the tender driven types (which need tyres?) compare in "tractive effort?"

in a word - variable!

As Mike says, it can be variable.   It's usually important to have weight over the driving wheels to aid traction. Old metal-bodied Farish locos were therefore ideally placed for loco drive, but the downside was less detailed bodies.  Arnold managed it pretty well though.

Tender drive has been popular with many manufacturers for decades, it allows for fine detail, "see-through" space under boilers and between the frames etc.  The driven mechanism in the tender can usually be a variation of a plain and simple "power block", and lower geared to allow for better slow speed running and often with several traction tyres, assuming there is loco pickup and wiring to the tender.  Fleischmann generally took that approach from the start. Downsides can be that the loco wheels and rods etc. have to be exceptionally free running or they can stick and slide along the track which looks bad, and also some locos suffer from "crabbing" to the side because they're being pushed by the tender.

An in-between solution is loco drive but with the motor in the tender, connected by a drive shaft. It can be very effective and smooth, with room for a decent sized motor in the tender though we're back with the need for weight in the loco. The shaft can look a little conspicuous. With Dapol locos in particular it seems you need to be very careful with handling to avoid displacing/disconnecting the shaft.

Decent traction requires decent weight over the driving wheels. If you have gradients on a layout and a few carriages to pull a tender drive may not cut the mustard as my Farish class 5 hauling 6 carriages did not. I prefer the motor in the loco as my recent version Farish Coronation has, but second best is the motor in the tender with a Cardan shaft driving the wheels under the loco as Dapol does with quite a few of their locos. Third best is tender drive, but these can work nicely provided the mechanism is freely running as ntpntpntp has suggested and on level layouts where traction is not as likely to be an issue.

Webbo

I've had no issues with any of my Farish tender drive locos but my layout has no gradients and (best way I can describe it) I don't hang more than a 4-5ft length of stock off them. Even that can be affected by the weight of the stock. Although I have several, I don't like Dapol's cardan shafts and believe the drivers of my Dapol steamers are considering going on strike rather than face the danger of a rotating shaft next to their lugholes!

Quote from: Webbo on October 15, 2017, 01:40:10 AM
Decent traction requires decent weight over the driving wheels. If you have gradients on a layout and a few carriages to pull a tender drive may not cut the mustard as my Farish class 5 hauling 6 carriages did not. I prefer the motor in the loco as my recent version Farish Coronation has, but second best is the motor in the tender with a Cardan shaft driving the wheels under the loco as Dapol does with quite a few of their locos. Third best is tender drive, but these can work nicely provided the mechanism is freely running as ntpntpntp has suggested and on level layouts where traction is not as likely to be an issue.

Webbo

I don't think there is necessarily any definitive order of merit as to what is "best" in terms of haulage of the three options mooted. What it comes down to is two factors, weight (in the right place) and adhesion, the second often enhanced by use of traction tyres.

The later Farish tender-drives are excellent, most notably the B1/J39 tender which have prodigious haulage capacity, the A1/A2 is the same provided there are tyres on the rearmost two driven axles. Locking of wheelsets is a reported problem which can largely be prevented by carefully adjusted wiper pickups and extreme care when handling (do not pick up by the motion). Later tender driven locos use bushed axle pickups on the loco (J39 and A1/A2) thus completely eradicating the issue of wiper adjustment.

The recent Farish loco-drive models also tend to use traction tyres to overcome the limited space for traction weight, including the Duchess. Most of these locos have adequate haulage capacity in my own experience.

Tank locos have need to pick up off of all driven wheels but have more space for weight or in the case of the Jinty and 08 employ a hybrid metal/plastic body (also 03/04).

The exceptions to the tyre "rule" most recently are the Merchant Navy which has none (plenty of room for weight) the 4f which as a result has very limited traction and the Castle where general consensus is that haulage is limited, and the loco is especially exposed on gradients.

Tender-loco drive adds complexity plus a horrible cardan shaft through the cab. It does have the benefit of allowing more room for weight, but the Dapol locos (9F and B17 aside) still use traction tyred driving wheels to maximise adhesion.

So my view is that each has benefits and drawbacks in N but good design is paramount and trumps any particular drive type being "best".

Roy

Thanks for the opinions, it's still all new to me.
I'm buying used at the moment and I don't mind losing a little detail for the sake of traction and pulling power. I think a loco should "pull" but I will be trying the tender driven types in due course.

Quote from: Old Crow on October 15, 2017, 02:47:34 PM
Thanks for the opinions, it's still all new to me.
I'm buying used at the moment and I don't mind losing a little detail for the sake of traction and pulling power. I think a loco should "pull" but I will be trying the tender driven types in due course.

If, in your view, superior pulling power is worth giving up some fine detail for, then I suggest that you have a look at a Union Mills locomotive.  The overall 'look' is right, but there is not a lot of fine detail.  Pulling power is excellent.  They are tender drive with pickup on one side from the locomotive and the other side from the tender.  This arrangement is sometimes called 'American' style pick-up.  Two traction tyres fitted, on the insulated side, to the driven axles the tender.  They are very reliable indeed.  However, the range is all inside-cylinder tender locomotives.

Happy 'N' gauging.

John

Quote from: Roy L S on October 15, 2017, 02:26:58 PM
I don't think there is necessarily any definitive order of merit as to what is "best" in terms of haulage of the three options mooted....... my view is that each has benefits and drawbacks in N but good design is paramount and trumps any particular drive type being "best".

Absolutely.  There are good and bad implementations of all the types of mechanisms.  Overall, probably my best "pullers" and smoothest slow runners are tender-drive, but as I mentioned in my previous post I still have a few old metal bodied Arnold loco-drive models that are very strong.

I reckon my absolute strongest steamer is an Arnold Mallet which I've had since the 80s, it'll out-pull quite a few of my bogie d & e locos, but of course it has all 16 wheels driven and plenty of weight


The worst I've had over the decades have been the old Minitrix 2-6-0 Ivatt tender locos and their german equivalents with the same chassis.  No weight in the loco and stiff tender wheels due to pickup drag. They've all ended up stripped down for parts.

Now that's what I call traction!
I'm very new to all this and must say I'm surprised at the light weight of some items. But I'm sure I'll get used to much finer tolerances in all things "N"

All of the latest Farish locos, tender driven or loco driven run beautifully smoothly, but whichever drive method is present there are issues as follows.

1.  Variable strength/lack of strength- Farish have a real problem with milling of wheels for traction tyres- the reason WDs are so variable is that some have tyres that don't actually touch the rails.  When I pointed out to Bachmann at Quorn that A2s are variable and in some cases very weak with over-milled wheels the reply was "We thought we'd got over that problem, obviously not".  This to a problem that when the WD came out nobody was prepared to admit to......  It is a little sad that within our club the strongest Farish loco we have is a 2MT, and that by a country mile.  My four A2s have been treated (at a fiver a pop) to a second pair of tyred wheelsets.  The improvement is remarkable- the weakest formerly handled five bogies on the flat and now manages fifteen. (Alf's 2MT took 32)

2.  Split gears- another old chestnut that won't go away on tender driven locos.  I currently have a J39 away at BR Lines with a split gear, and A1 Kenilworth's second visit to BR Lines included a split gear replacement.

3.  Locking up- the worst of the tender drives for this is the 4MT.  The loco is quite light and it doesn't take much friction to cause lockups.  It is funny how many times I've watched a 4MT running along an exhibition layout with the driving wheels sliding, and the operator hasn't noticed it.  It isn't just a Farish thing- Fleischmann locos are just as bad.

I've just found a traction tyre in the fiddle yard at the end of the Peterborough show- the first I've lost, after 16 shows with this layout and quite a number of Farish locos running on previous/other lines.  They do have a reputation of coming off easily- but with care they last.  Again, lasting longer than a couple of Fleischmann diesels on a previous layout.

ALL makes of loco have their plus and minus points.  My fleet is big enough to be able to compare them, and with Farish, Dapol and Union Mills all represented in the Hawthorn Dene fleet, there isn't a lot to choose between them.  All will do two days hard work at a show- with the occasional lemon such as my A1 Kenilworth which is back at BR Lines for the 4th time.  Having run Continental on Furtwangen Ost for 18 shows the grass isn't greener over there.....

Les

Quote from: Les1952 on October 16, 2017, 11:55:51 PM
3.  Locking up- the worst of the tender drives for this is the 4MT.  The loco is quite light and it doesn't take much friction to cause lockups.  It is funny how many times I've watched a 4MT running along an exhibition layout with the driving wheels sliding, and the operator hasn't noticed it.  It isn't just a Farish thing- Fleischmann locos are just as bad.

I totally agree about the 4MT but I have found a solution by very lightly oiling the motion

This is very interesting to a newbie just starting with "N". I'm buying used at present, which means Poole or Early Chinese. Got two Coronation Pacific duchesses and both run well. The older Poole one will probably need a good lubrication - it needs more voltage than the later one - an early Chinese build to the same spec which is very free running indeed. Both have a bit of weight to them. As I said earlier, I'd forgo a bit of detail for traction and I can't help thinking locos should pull.

Quote from: Old Crow on October 17, 2017, 01:05:50 PM
The older Poole one will probably need a good lubrication

Careful not to overdo it! If you can see the lube you've used too much, and using too much is probably as bad as using none.

Quote from: newportnobby on October 17, 2017, 01:14:40 PM

Quote from: Old Crow on October 17, 2017, 01:05:50 PM
The older Poole one will probably need a good lubrication

Careful not to overdo it! If you can see the lube you've used too much, and using too much is probably as bad as using none.

Agreed, I've had to do far more "de-oiling" to service people's locos than I've ever had to actually lubricate.

The difference in voltage could imply the motor commutator is dirty or needs new brushes, or the motor is getting old and losing magnetism.