Bachmann 94xx

[Pinehill]

1 hour ago, dibber25 said:

Yes, that's the best choice in the circumstances. I sympathise with those who have large collections and no intention of going DCC - I'm one of them. I run my British-outline on a Gaugemaster analog controller that' s best part of 20 years old and it's fine with the modern motors as well as the old. During the lock-down its been used to test review models - including the 94XX and our 16XXs - and they've been fine. I have DCC on my North American layout because I had a far smaller commitment in locos that I couldn't easily fit with decoders. Even so, I have one or two special models that I detailed and repainted, that I can no longer run. (I also have vinyl records - with a cheap modern player and VHS tapes which are now useless but which I don't like to throw away!) (CJL)

Dibber25, was that analog controller you used a feedback unit to test review the 94xx or non feedback? I can see that there is no problem with using a non feedback unit.

[adb968008]

3 hours ago, MikeParkin65 said:

It does depend on what you define your interest in the hobby to be. If it is collecting new loco's (and nothing wrong with that) then you have the choice of changing your controller, chipping the loco's, buying but not running or simply not buying.  Personally I'd go DCC but 50+ loco's is a significant expense. Best second option is a new DC controller I'd have thought.

I have a way lot more than 50 engines.. ive got 20 class 66s just this month.

if I went DCC i’d have a lot less engines for sure !

 

[stewartingram]

I have homebuilt Wireless World controllers, from 1971. I have a layout under construction, but it will eventually extend outward from the garage, so as yet no fiddle yard, just limited shunting. The controllers have however been used over the years on various other layouts with no detrimental effects. I achieve very good slow running, and starts/stops with the design. I do maintain the locos properly, and add extra pickups. I have over 150 locos in my fleet (not a boast btw), admittedly many that are basically "bought because I like" rather than true layout locos, so DCC is NOT an option, along with the cost of chips. Besides, I have no interest in computer style control, light or sound. I used to work in electronics, and am glad to get away from it to do modelling. I still have some X04 era motors, and even Triang chassis, but still achieve very good control throughout. A Triang chassis will creeeeeep up to a wagon with t/l couplings so slowly that you can see the hook gradually climb over the loop of the next coupling. Why should I lose all that by buying an inferior dc controller? I also believe - firmly - that a chassis MUST always run well BEFORE conversion to DCC. You cannot overcome mechanical defects by adding a chip! I have a small number of modern/coreless locos which as yet have shown no faults with the WW controllers, which use PWM & variable feedback circuitry. I've looked at some of these and thought they had coreless fitted just because they could have, not because of necessity. If any burn out, I'll replace with a conventional motor, or build a new chassis. I hate to pick on one model at all, but the J70 is one example. I have that, and also a similar Y6 0-4-0 etched kit with similar internal details, and the small conventional motor is hidden just as well. It can be done. Not that the J70 is a poor model; I bought one (eventually, the coreless put me off originally) and have no regrets.

 

Stewart

[Miss Prism]

The Portescaps in the Bodmin locos worked with Wireless World controllers for many years without impairment. The waveform output was a bit fierce though, and they were replaced by the wonderful Compspeed Fs.

 

[cctransuk]

2 hours ago, Pinehill said:

 

I already have an alternative quality non feedback controller! The locos I have just don’t run as smoothly with it as they do with the feedback unit. To run the new coreless models means losing the running qualities of the existing locos or changing the controller each time a different type of motor is run. Impractical & a pain.

 

in that case, I'm afraid that you are overstating the difficulties.

 

A simple two pole / two way / centre off switch, to apply the appropriate controller to the specific loco, is all that is required.

 

Simples!

 

John Isherwood.

[Izzy]

I think this issue of coreless motors is one that will become increasingly common. In very general terms coreless are seen as ‘green’ since they consume less power, so they are being produced in preference to cored. Just in the same way that newer types of light bulbs are now being made.

 

For model railway use the big difference is that the coreless design doesn’t have the iron mass that cored do, so cannot cope with and absorb the same levels of heat generated by being subjected to low frequency PWM - feedback- that most/all DC PWM  controllers produce. This issue is exacerbated by their very quick reaction to small changes in current and the ‘jittery’ performance that can often result. Quite a few of the more efficient cored motors produced today react in a broadly similar manner. By contrast DCC decoders use high frequency PWM and the levels of BEMF feedback can also be adjusted with many of the better decoders. 
 

This lack of backwards compatibility for DC users is analogous with present day computing where newer equipment and firmware, latest O/s etc, won’t always support older applications or hardware. I fear there is no easy answer to all of this and each individual will have to take the path that is best for them. 
 

Izzy

[dibber25]

3 hours ago, Pinehill said:

Dibber25, was that analog controller you used a feedback unit to test review the 94xx or non feedback? I can see that there is no problem with using a non feedback unit.

It's a Gaugemaster Model D - probably pre-dates feedback and was, if I recall correctly, a review sample in its own right!  (CJL)

[The Johnster]

My GM power controller was bought in, IIRC, about 1984 and is thus 36years old.  It works perfectly with all my current production can motors. 

[No Decorum]

17 hours ago, dibber25 said:

As a general principle, manufacturers move forward with technology, sometimes by choice and other times because they are obliged to. (CJL)

That’s true. Eventually, old technology is left behind and any possessor of it is left high and dry. Television is a very good example. In the model railway world, track and wheel standards have been refined in small steps such that some very old locomotives will not run properly on some modern track. I can also understand that the greater efficiency of coreless motors is a substantial advantage when powering drones.

 

My gripe with the use of coreless motors in model railways is that they are not a move forward. The lack of an iron core makes them less smooth at very low speeds and traditional motors have been produced which are so small that they seem to dispose of the size argument. The efficiency of coreless motors is not an advantage either, given the small amounts of power needed to run a model railway. On the other hand, coreless motors bring with them such problems that they seem to me a move backwards in technology. Remember Windows 8?

 

Hornby is much criticised (by me as well as many others) for its backwardness in DCC compatibility but the power, silence and smoothness of the skew-wound, five-pole motor Hornby uses is ahead of anything else in the business.

[The Johnster]

So, the iron core of a traditional motor acts as a sort of flywheel?  Makes sense, but the effect with our small motors at low voltages must be minimal.  In practice, the difference is not much and there is probably an overlap in slow running performance; much will depend on the ability of the motor to run freely at low rpm while providing usable torque to start heavy trains smoothly, and build quality is more important than the presence or otherwise of a core.  
 

One must trust Bachmann to have sourced a good quality motor for the 94xx, and wait and see how it performs at low speeds, but this is the same for all locos!

[No Decorum]

35 minutes ago, The Johnster said:

So, the iron core of a traditional motor acts as a sort of flywheel?  Makes sense, but the effect with our small motors at low voltages must be minimal.  In practice, the difference is not much and there is probably an overlap in slow running performance; much will depend on the ability of the motor to run freely at low rpm while providing usable torque to start heavy trains smoothly, and build quality is more important than the presence or otherwise of a core.  
 

One must trust Bachmann to have sourced a good quality motor for the 94xx, and wait and see how it performs at low speeds, but this is the same for all locos!

Ah yes, I note your reservations about flywheels. One of the problems with flywheels is that, because of space restrictions, their diameter usually matches the diameter of the motor, whereas to be truly effective, they need to be a good deal bigger. As you have pointed out, they are good at low speeds but not at very low speeds. Like yourself, I value smooth very low speed running. In my view, it is necessary not only for shunting because every locomotive, no matter how big and imposing, runs at very low speed when stopping and starting. I’ve cited the 3' rule before. At that distance, fine detail may not be obvious but jerkiness is.

 

Build quality is certainly important – probably more important than the type of motor. It has often been pointed out that a three-pole motor can be as good as a five-pole one. Bachmann three-poles may not be quite as good as Hornby five-poles but they do run well, by and large. When Hornby dug itself into a well-motivated hole with “design clever”, three-pole motors were adopted with a flywheel used to attempt to overcome their shortcomings. I wonder how long it would have taken someone to go through a box of motors and test each one, discarding the bad items. It clearly wasn‘t done with the result that quite a few rotten ones found their way into Hornby models. Others seemed fairly acceptable.

[Dunsignalling]

52 minutes ago, The Johnster said:

So, the iron core of a traditional motor acts as a sort of flywheel?  Makes sense, but the effect with our small motors at low voltages must be minimal.  In practice, the difference is not much and there is probably an overlap in slow running performance; much will depend on the ability of the motor to run freely at low rpm while providing usable torque to start heavy trains smoothly, and build quality is more important than the presence or otherwise of a core.  
 

One must trust Bachmann to have sourced a good quality motor for the 94xx, and wait and see how it performs at low speeds, but this is the same for all locos!

An obvious way to overcome the low mass difficulty with coreless motors would be is to have them revving much faster and driving through gears with greater reduction.

 

Treating them as direct replacements for higher-mass cored units is bound to expose the differences.

 

John

[MikeParkin65]

4 hours ago, No Decorum said:

That’s true. Eventually, old technology is left behind and any possessor of it is left high and dry. Television is a very good example. In the model railway world, track and wheel standards have been refined in small steps such that some very old locomotives will not run properly on some modern track. I can also understand that the greater efficiency of coreless motors is a substantial advantage when powering drones.

 

My gripe with the use of coreless motors in model railways is that they are not a move forward. The lack of an iron core makes them less smooth at very low speeds and traditional motors have been produced which are so small that they seem to dispose of the size argument. The efficiency of coreless motors is not an advantage either, given the small amounts of power needed to run a model railway. On the other hand, coreless motors bring with them such problems that they seem to me a move backwards in technology. Remember Windows 8?

 

Hornby is much criticised (by me as well as many others) for its backwardness in DCC compatibility but the power, silence and smoothness of the skew-wound, five-pole motor Hornby uses is ahead of anything else in the business.

Agree  - all of my Hornby steam outline loco's are smoother and more controllable at very low speed than any of my Bachmann steam outline loco's. The latest Terrier is the smoothest runner I have ever encountered and is significantly quieter and smoother than the J72. Both are fitted with Zimo chips (the J72 with sound) and I have not altered any of the motor parameters - this is out of the box performance. I hasten to add I am not at all dissatisfied with my J72 and remain in the market for a 94xx (its my railway and I'll run what I like lol)

[The Johnster]

2 hours ago, Dunsignalling said:

An obvious way to overcome the low mass difficulty with coreless motors would be is to have them revving much faster and driving through gears with greater reduction.

 

Treating them as direct replacements for higher-mass cored units is bound to expose the differences.

 

John

I hope not!  This sounds like a reversion to the pancake philosophy of 40 odd years ago, also using high revving motors driving through gear trains of nylon reduction cogs to achieve reasonable rpm at the driving wheels.  The cogs were unreliable and prone to splitting, and induced a degree of friction that defeated any chance of good slow running or smooth start/stops.  Hoping not does not make you wrong, though, John, and while I think the 94xx will be fine as a slow runner, I reckon you are right in that coreless will become the norm over the next decade or so as it becomes harder for Chinese factories to source good quality cored motors suitable for use in model railway locos, 

 

A long term answer might be multiple smaller motors directly driving each axle, so that the 'lumpiness' is cancelled out.  I am fortunate in that the 94xx is probably going to be the last of my RTR loco purchases (unless someone brings out a decent 2721, 1854, or Collett 1938 31xx), so I've got my purchases in before it hits the fan!

[D9020 Nimbus]

22 hours ago, dibber25 said:

We might prefer VHS tapes or vinyl records but it means we can't watch DVDs or download music. It's a hard fact, but the same is happening with model locomotives.

Not quite the same situation—and not even true: having vinyl records doesn't stop you from downloading music!

 

The issue with model railways is that you might want to run different types of locos from different eras at the same time. If an old loco needs a different type of controller to perform at its best, then it becomes a problem. I suspect not being able to use electronic track cleaners is possibly more of an issue for some.

[dibber25]

15 minutes ago, D9020 Nimbus said:

Not quite the same situation—and not even true: having vinyl records doesn't stop you from downloading music!

 

The issue with model railways is that you might want to run different types of locos from different eras at the same time. If an old loco needs a different type of controller to perform at its best, then it becomes a problem. I suspect not being able to use electronic track cleaners is possibly more of an issue for some.

I thought we were discussing replacing old equipment with new? I can't download music on my record-player. (CJL)

[cctransuk]

20 minutes ago, D9020 Nimbus said:

The issue with model railways is that you might want to run different types of locos from different eras at the same time. If an old loco needs a different type of controller to perform at its best, then it becomes a problem.

 

As I posted yesterday - this issue is getting out of proportion!

 

A simple two pole / two way / centre off switch, to apply the appropriate controller to the specific loco, is all that is required.

 

https://www.rapidonline.com/sci-ta203a1-dpdt-c-o-min-toggle-switch-75-0145

 

A task that anyone who can attach a controller to a layout can achieve;

 

John Isherwood.

[No Decorum]

22 minutes ago, cctransuk said:

 

As I posted yesterday - this issue is getting out of proportion!

 

A simple two pole / two way / centre off switch, to apply the appropriate controller to the specific loco, is all that is required.

 

https://www.rapidonline.com/sci-ta203a1-dpdt-c-o-min-toggle-switch-75-0145

 

A task that anyone who can attach a controller to a layout can achieve;

 

John Isherwood.

When I first set up my present layout, I wired up four panels of switches, each switch wired to the same stretch of track as the corresponding switches on the other panels. A controller was wired to each panel. It might be called cab control but I hesitate to use the term for my unsophisticated arrangement. When I first trialled DCC, I removed an analogue controller and replaced it with a DCC one. I’m now on my third generation of DCC controller but my old faithful DC ones continue on. I find that switching one circuit of track to DC and another to DCC works and I can run a DC loco on one at the same time as a DCC on the other. Of course, I need to be very careful that I don’t confuse the two and inadvertently switch both types of controller onto the same track section or switch DCC to a section occupied by a DC loco. I bar myself from the layout if I’ve had even a sip of beer!

[Wickham Green too]

On 09/12/2020 at 16:07, No Decorum said:

......... Of course, I need to be very careful that I don’t confuse the two and inadvertently switch both types of controller onto the same track section or switch DCC to a section occupied by a DC loco. ......

Any competent signal engineer would interlock you out of that problem !

[adb968008]

I just use Connector blocks and male pins.

 

Ive 3 controllers bus wired around the layout, with several pairs of male connector block pairs hanging in each corner of the loft (my 4 signal boxes).

Then each track section is wired to a 2 of 12 port connector block bank in pairs to the track terminating in the corresponding corners of the loft. Above is a label as to which circuit it feeds. (All my track is isolated on both rails, except ends of sidings).

Setting a route involves taking a pair of controller bus male pairs  to the right sets of female track circuits around the room to make the circuit, setting points and off you go.

The intention was to wire the females to a centralized board in the loft, but i reached my “it will do” moment some while back, and exercise does me good.

 

It works as it physically prevents me putting two controllers to the same track, though occasionally I forget to unplug one when i’m done.

Ive thought for me to go DCC, all I need to do is add a DCC to one of those buses, and make every female live to it, or indeed just continue as I do now, but with a DCC on one bus and DC on the others.

 

There is a “cheat” third way... Add a DCC controller, then immediately introduce a DCC chip, wiring the DC motor outputs from it  onto one of my existing DC bus to the male connectors and hence connect my female track circuits as I do today...immediately everything becomes DCC though obviously the same 1 at a time applies on that bus, I could bank 2 further DCC chips to my other 2 buses... that way ive 3 bus lines live off of 1 DCC controller for the cost of just 3 DCC chips.

 

Edited December 13, 2020 by adb968008

[The Johnster]

Your third option cheat is something I'd never thought of, basically converting entire circuits to a sort of ersatz DCC.  It is of interest because, although not allowing individual control of locos and still requiring the DC type isolated sections, it would presumably allow the finer DCC control of locos, which is something I am interested in.  I will give this a serious thinking session!

[The Stationmaster]

2 hours ago, The Johnster said:

Your third option cheat is something I'd never thought of, basically converting entire circuits to a sort of ersatz DCC.  It is of interest because, although not allowing individual control of locos and still requiring the DC type isolated sections, it would presumably allow the finer DCC control of locos, which is something I am interested in.  I will give this a serious thinking session!

Going a long way OT.

 

Surely it won't be as good as DCC because the power loss between the feed to the track and a loco motor will meet much more resistance getting to the motor than would the higher track voltage transformed etc on an individual loco?

[The Johnster]

You're no doubt right, Mike; got my hopes up for a minute there!

[scots region]

https://www.youtube.com/watch?v=E2BiCpx0shk

[mikesndbs]

I wonder how a voltage limited (by supply) PWM at 20kHz would work on coreless?