Jump to content
 

Realtrack Class 156


charliepetty
 Share

Recommended Posts

  • RMweb Gold
7 minutes ago, charliepetty said:

The Realtrack Model is at the Higher end of the DMU price bracket, but it has been designed for DCC & Sound, even the Non Sound versions have 2 x Pre-Fitted speakers 'Just in Case'.

See an independant review below:

 

 

The Lima/Hornby Class 156 just isn't in the same league as a Realtrack Class 156, not even sure if it was a really good representation at the time when it was released as I remember the moaning about when it first came out, especially the moulded underframe.  It's like comparing a Lada to a Hyundai Ioniq.

Link to post
Share on other sites

  • RMweb Premium

I think its a case of you're damned if you do and damned if you don't, @charliepetty. The Realtrack model is a fantastic model, and if you'd designed it with one power bogie and no provision for sound, just as many people would complain as there are who would prefer it without the extra complications of being sound-ready. It's the same argument as DC versus DCC-ready years ago ("why should we DC modellers pay for DCC sockets" etc). Or the same as lighting - fir bright LEDs and people who like lights will love that they can see and play with them, while others will want dim representations of incandescent bulbs.

 

If I were starting out now, I'd buy the Realtrack model, it's massively better than the Lima/Hornby one, despite any (perceived or real) flaws it may have, likewise the new Bachmann 158. 

  • Agree 2
Link to post
Share on other sites

I know several have brought up the lighting issue on the older WIPAC style (eg Provincial) units previously. I have had a thumb through the pages since I last looked but cant see if any further comment has been made regarding any progression on releasing the correct pattern lights? It was mentioned some time ago IIRC that once initial costs had been covered then producing some tooling mods to correct such compromises would likely happen.

 

I know there's a certain number of us who are still holding back due to this and further number who did go ahead with the compromise version (given how poor a standard Lima/Hornby unit is) but suggest they would put these straight on ebay and upgrade if the correct lighting cluster was modelled. Its difficult to persuade me as I already have an 'acceptable' detailed no traction tyre, underframe kitted unit with lights so have thus held back on any not too cheap compromise model.

 

Just to add I appreciate and understand Realtrack's initial position, just looking to see if theres an update/anything on the horizon.

 

TIA

  • Agree 1
Link to post
Share on other sites

7 hours ago, sanspareil said:

I have had a thumb through the pages since I last looked but cant see if any further comment has been made regarding any progression on releasing the correct pattern lights?

 

The conversation a few posts ago is on that exact topic I believe.

 

Edit, sorry, wrong thread! Look here:

 

 

Edited by TomScrut
  • Thanks 1
Link to post
Share on other sites

Just unboxed my lovely Leeds-Carlisle 156. WOW. So smooth and such detail.

Two questions

1. Is it worth running in the cars seperately so that each mechanism is bedded in withoit interference from its partner?

 

2. One of my windscreen wipers is mounted with the arms pointing down (so blade at weird angle). Any advice on how i can correct this, preferably without using my spare wiper. How is it glued on?

 

Link to post
Share on other sites

Its an interesting point about twin sound in a twin car dmu.  Anyone who's put the twin tts chips into a hst will recall the 'interesting' stereo effect.  And when i say interesting, i mean bloody awful. 

 

I really don't think it's as simple a matter as a twin car sounds best with twin sounds.  IIRC, the realtrack units are out of sync, producing a much more realistic sound of two motors working alongside each other , rather than simply doubling the sound.  But Charlie can answer that one better than me.

Link to post
Share on other sites

2 hours ago, G-BOAF said:

Just unboxed my lovely Leeds-Carlisle 156. WOW. So smooth and such detail.

Two questions

1. Is it worth running in the cars seperately so that each mechanism is bedded in withoit interference from its partner?

 

2. One of my windscreen wipers is mounted with the arms pointing down (so blade at weird angle). Any advice on how i can correct this, preferably without using my spare wiper. How is it glued on?

 

Just try moving it back in position, IF it drops off I suggest to bit of white PVA glue.

 

Running In.  Seperatly OR Together.

 

PPS If DCC we have Sound OR Non Sound Decoders.  A Little Tip.

 

The Sound fitted versions are cheaper than buying from retailers then buying the decoders!!!!

 

Charlie

Link to post
Share on other sites

On 27/12/2020 at 01:17, sanspareil said:

I know several have brought up the lighting issue on the older WIPAC style (eg Provincial) units previously. I have had a thumb through the pages since I last looked but cant see if any further comment has been made regarding any progression on releasing the correct pattern lights? It was mentioned some time ago IIRC that once initial costs had been covered then producing some tooling mods to correct such compromises would likely happen.

 

I know there's a certain number of us who are still holding back due to this and further number who did go ahead with the compromise version (given how poor a standard Lima/Hornby unit is) but suggest they would put these straight on ebay and upgrade if the correct lighting cluster was modelled. Its difficult to persuade me as I already have an 'acceptable' detailed no traction tyre, underframe kitted unit with lights so have thus held back on any not too cheap compromise model.

 

Just to add I appreciate and understand Realtrack's initial position, just looking to see if theres an update/anything on the horizon.

 

TIA

Sorry No.

Link to post
Share on other sites

On 21/12/2020 at 10:26, Barry O said:

How do you expect them to be better matched? Every motor has slightly different characteristics..as does gearing.

 

 

Baz

 

So how would that work if you buy the Analog DC version of this DMU, given that it is designed with two motors? Would you expect the motors and gears to match? 

Link to post
Share on other sites

51 minutes ago, APT Fan said:

 

So how would that work if you buy the Analog DC version of this DMU, given that it is designed with two motors? Would you expect the motors and gears to match? 

 

These things (as in model railway stuff in general) hardly ever match speed wise. They don't even match their own speeds in the opposite directions most of the time.

 

DC is a completey different situation to most DCC use, the difference with a DC Vs DCC is that with DC it doesn't really matter as the slower motor will do less of the work (draw less current) and therefore for a given voltage they'll even themselves out. Likewise with DCC without back EMF enabled (but most decoders have BEMF enabled by default).

 

With back EMF enabled on DCC it's a different kettle of fish, as the chip uses the back EMF voltage from the motor as a way of deducing the speed of the vehicle and attempts to maintain constant speed for the given speed step. Therefore if a car is a scale 5mph faster than the other one you'll end up with one or more of the following problems:

 

1. Jerky driving as the cars are fighting each other as their target speeds are different. So they will slow down and speed up to try and do what they are each trying to do.

2. Wheel slip on one or both units as they are trying to do different speeds

3. Pushing against the coupler causing it to bend/whatever (when in corners)

4. A hypothesis I have is any force not taken by wheel slip would be driving back through the gearboxes, which normally have a worm gear in and so may increase wear.

 

This is based on my experience with Bachmann 37s and speed profiling quite a few locos of dlsame types, but I don't see why it would be any different on a 156. The solution is to match the speeds by setting the CVs up properly, turning BEMF off or if using something like iTrain, speed profiling the cars.

  • Like 1
  • Agree 1
Link to post
Share on other sites

  • RMweb Premium
1 hour ago, APT Fan said:

 

So how would that work if you buy the Analog DC version of this DMU, given that it is designed with two motors? Would you expect the motors and gears to match? 

You said you were an engineer......

 

Baz

Link to post
Share on other sites

  • RMweb Premium
1 hour ago, TomScrut said:

 

These things (as in model railway stuff in general) hardly ever match speed wise. They don't even match their own speeds in the opposite directions most of the time.

 

DC is a completey different situation to most DCC use, the difference with a DC Vs DCC is that with DC it doesn't really matter as the slower motor will do less of the work (draw less current) and therefore for a given voltage they'll even themselves out. Likewise with DCC without back EMF enabled (but most decoders have BEMF enabled by default).

 

With back EMF enabled on DCC it's a different kettle of fish, as the chip uses the back EMF voltage from the motor as a way of deducing the speed of the vehicle and attempts to maintain constant speed for the given speed step. Therefore if a car is a scale 5mph faster than the other one you'll end up with one or more of the following problems:

 

1. Jerky driving as the cars are fighting each other as their target speeds are different. So they will slow down and speed up to try and do what they are each trying to do.

2. Wheel slip on one or both units as they are trying to do different speeds

3. Pushing against the coupler causing it to bend/whatever (when in corners)

4. A hypothesis I have is any force not taken by wheel slip would be driving back through the gearboxes, which normally have a worm gear in and so may increase wear.

 

This is based on my experience with Bachmann 37s and speed profiling quite a few locos of dlsame types, but I don't see why it would be any different on a 156. The solution is to match the speeds by setting the CVs up properly, turning BEMF off or if using something like iTrain, speed profiling the cars.

Would imagine that on DC, options 2, 3 & 4 from your list are all a possibility.

Although I have a DC powered realtrack 156, & it runs beautifully !!

 

cheers,

Phil.

Link to post
Share on other sites

2 hours ago, Phil Mc said:

Would imagine that on DC, options 2, 3 & 4 from your list are all a possibility.

Although I have a DC powered realtrack 156, & it runs beautifully !!

 

cheers,

Phil.

I am not quite sure what this overall conversation is about !!!!

 

What i do know is after sales of:

2500 Scotrail (5 Versions)

1500 EMT (4 Versions)

2500 Provincial (5 Versions)

 

We don't seem to have had this issue.

 

I find it amazing that 95% of customers seem happy, but roughly 5% don't.

 

I have noticed over 8 years one guy has returned 5 units (143, 144 & 3 X 156s) due to derailing on 1st Radius track, even though the box states don't run them on 1st Radius.

 

Hi comments were 'All my other stock works'

 

I was really funny a while back on talking to Kernow about a specific issue with a customer, there comments were:  Sounds like Mr Dean in Preston.     THEY WERE CORRECT.

 

Charlie.

 

Dont forget a Yporkshire saying: Now,t as queer as folk'

143 Happy Snap.JPG

Edited by charliepetty
  • Like 1
  • Funny 3
Link to post
Share on other sites

2 hours ago, TomScrut said:

 

These things (as in model railway stuff in general) hardly ever match speed wise. They don't even match their own speeds in the opposite directions most of the time.

 

DC is a completey different situation to most DCC use, the difference with a DC Vs DCC is that with DC it doesn't really matter as the slower motor will do less of the work (draw less current) and therefore for a given voltage they'll even themselves out. Likewise with DCC without back EMF enabled (but most decoders have BEMF enabled by default).

 

With back EMF enabled on DCC it's a different kettle of fish, as the chip uses the back EMF voltage from the motor as a way of deducing the speed of the vehicle and attempts to maintain constant speed for the given speed step. Therefore if a car is a scale 5mph faster than the other one you'll end up with one or more of the following problems:

 

1. Jerky driving as the cars are fighting each other as their target speeds are different. So they will slow down and speed up to try and do what they are each trying to do.

2. Wheel slip on one or both units as they are trying to do different speeds

3. Pushing against the coupler causing it to bend/whatever (when in corners)

4. A hypothesis I have is any force not taken by wheel slip would be driving back through the gearboxes, which normally have a worm gear in and so may increase wear.

 

This is based on my experience with Bachmann 37s and speed profiling quite a few locos of dlsame types, but I don't see why it would be any different on a 156. The solution is to match the speeds by setting the CVs up properly, turning BEMF off or if using something like iTrain, speed profiling the cars.

 

 

Thanks that's a really good post and its prompted further reading for me. It is interesting to read BEMF described as closed loop control for speed control when really the speed has been estimated from the BEMF. True closed loop speed control would use speed measurement too, obviously not very practical for these applications. I can see why the BEMF loops would fight each other, I've read that perhaps tuning could improve this but to me it feels like you are chasing the wrong parameter (speed).

 

Once you've carried out 'speed profiling' do you ever have to revisit it for I don't know gear wear or given that these motors are permanent magnetics, any loss of 'magnetism' with age?

 

I still can't quite reconcille the comment about 'they'll even themselves out' on DC though. I'm just thinking about putting two locos on a DC test track when one is clearly faster than the other one, it eventually catches the other one up and starts pushing the other one. It doesn't look good and can't be healthy, okay that's an extreme example but any discrepancy is probably not a good idea. 

Link to post
Share on other sites

2 hours ago, Phil Mc said:

Would imagine that on DC, options 2, 3 & 4 from your list are all a possibility.

Although I have a DC powered realtrack 156, & it runs beautifully !!

 

cheers,

Phil.

 

41 minutes ago, APT Fan said:

pushing the other one


Yes but it is different because the "push" from the faster one actually just means that one does more work than the other as they are simply being supplied with a voltage and so there is no governance, if the motor has less resistance (as it is being pushed) it will speed up accordingly and the one doing the pushing will slow down slightly as it has a larger load, and this can happen at the wheels I think without thinking too much about it.

 

With BEMF the slower unit will back off when it realises it is going faster than it thinks it should be, as it is trying to maintain a particular speed with feedback which exacerbates the issues if the two speeds are different.

 

If you took the gearbox out of a DC loco and sat it on the track the unloaded motor would reach the maximum speed it could for that particular voltage (which would be pretty much BEMF=Track voltage IIRC as load is negligible). If you did the same thing with the BEMF enabled chip it would rotate at the same speed it would have done driving down the track as the chip accounts for the motor being unloaded.

 

41 minutes ago, APT Fan said:

use speed measurement too

 

You set the reference/max BEMF voltage in the CV settings (CV53 on ESU at least, this is obtained by speed measuring the loco at full tilt and adjusting the CV to get absolute top speed from it), and therefore my understanding is that because the relationship between motor speed and BEMF voltage is linear (IIRC) then the decoder knows the BEMF voltage for any speed in the motors range of operation. As you then set the max motor speed in the CVs to the prototypical top speed of the loco (CV5), then 2 (in theory) identical locos should act roughly the same if set up properly.

 

The BEMF itself looks to me like it uses a PI control to smooth responses out, where K (proportional) is the strength of the response to change in drag/speed and I (integral) accounts for the inertia of the system as a whole (which will itself be a balancing act of drag).

 

This is all my understanding of it rather than statement of fact but there is a combination of experience with these issues and engineering theory behind it.

Edited by TomScrut
Link to post
Share on other sites

45 minutes ago, charliepetty said:

I am not quite sure what this overall converstaion is about !!!!

 

What i do know is after sales of:

2500 Scotrail (5 Versions)

1500 EMT (4 Versions)

2500 Provincial (5 Versions)

 

We don't seem to have had this issue.

 

I find it amazing that 95% of customers seem happy, but roughly 55 don't.

 

I have noticed over 8 years one guy has returned 5 units (143, 144 & 3 X 156s) due to derailing on 1st Radius track, even though the box states don't run them on 1st Radius.

 

Hi comments were 'All my other stock works'

 

I was really funny a while back on talking to Kernow about a specific issue with a customer, there comments were:  Sounds like Mr Dean in Preston.     THEY WERE CORRECT.

 

Charlie.

 

Dont forget a Yporkshire saying: Now,t as queer as folk'

 

I'm not sure there has been any criticism of the actual product on here. I have questioned the pricing, which has now been clearly explained to me which I accept the answer. I also appreciate that my questions were due to a lack of knowledge but I'm here to learn.

 

I also think that a lot of other forum members are here to learn too and are genuinely interested in how these things work. Just because people question things, especially within this sort of media does not make it a criticism and I really wouldn't be too sensitive about it if I were you.  

Link to post
Share on other sites

42 minutes ago, APT Fan said:

Once you've carried out 'speed profiling' do you ever have to revisit it for I don't know gear wear or given that these motors are permanent magnetics, any loss of 'magnetism' with age?

 

The biggest issue I think is the general maintenance of the locos. Internal friction plays quite a big part in the speed profiling side (when getting Vmax) so something that's not been run for a while or very often might need some running in before profiling. OTOH assuming the scale prototypical Vmax is a lot less than model Vmax the BEMF helps as it just accounts for the extra drag.

 

I haven't experience of it over a prolonged time as I have only been back in the hobby a year or so and most of my stuff is fairly new. So I cannot say about the reduction in magentism but I have also yet to hear it mentioned

Link to post
Share on other sites

The new Class 156 units are planned to be probably:

 

156420 Northern Midnight Blue.

156466 Northern Midnight Blue.

156459 Northern White 'Bubbles'

156496 Northern White 'Bubbles'

 

Strathclyde has not been decided yet.

 

 

 

Charlie

Edited by charliepetty
  • Like 2
Link to post
Share on other sites

2 minutes ago, charliepetty said:

We seem to be drifting away from the actual thread here.

 

Charlie

 

Sorry, I'll (figuratively) put a sock in it.

 

I aren't suggesting there are any issues with your units BTW (I have one on pre order), what I am talking about applies to any train with more than one motor in it and a lot of people won't notice nor care of the differences.

 

1 hour ago, charliepetty said:

due to derailing on 1st Radius track, even though the box states don't run them on 1st Radius.

 

I haven't even got or read a manual and I know that as you very explicitly explain it will cause issues on the listings for them. Some people just don't read stuff.

 

They must have a very specific taste in stock if everything else they have runs on 1st radius!

 

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...