Mechanical Cam ‘Chuffer’

[Thunderforge]

I had a Hornby Railroad LNER tender engine a while ago with what I can only describe as a ‘mechanical cam chuffer’. One of the tender axles had a cam with a rough surface which rotated against a little piece of spring steel with a similarly rough surface. The sound was amplified by the empty tender body to give a reasonable good ‘chuf’ which directly sped up and slowed down with the loco. I thought it was an amazingly simple and effective and maybe I could replicate it myself.

Before I started I wondered if anyone else has tried it and what you might recommend for the ‘rough texture’? Course sandpaper?

[Londontram]

I can't recall what loco it was but I had one of these with this in the tender. I recall it worked well enough but like smoke units I find (even modern DCC ones) a bit gimmicky.

It should be easy to rig up a simple cam on an axle with say a bit of sandpaper on a flexible strip of brass that is fixed to the tender body but is set to brush against the high spot of the cam on every revolution.

As I say its horses for corses.

[The Johnster]

Whatever floats your boat, but I reckon something similar to replicate diesel sound would be more effective.  A steam loco only makes chuffing noises when it is working, and runs more or less silently (clanks, squeaks, knocks, and swearing firemen excepted, of course) when it is coasting or slowing down.  Diesels are noisy all the time.

 

I have to say that the DCC noises that come out of steam outline models do not seem to me to be much of an advance on this idea, white noise with no regard to the throttle or reverser settings.  Steam locos did and do not just go chuff chuff all the time.  GW ones sound more like woof woof...

 

But, to ignore my negativity, you will want to make a cam around one of the tender axles which replicates either 4 (for a two or 4 cylinder loco) or 6 (for a 3 cylinder one) (we will leave Lord Nelsons out of the discussion for now) per revolution of the driving wheel, which will involve either some complex mathematics working out the length of the circumference of the driving wheels, or, which would be my preferred method, trial and error.  As I recall, the old Triang Hornby was none too accurate in this respect, and most people regarded it as a bit of a gimmick, but good fun for the kids in a train set.  if you were doing it for a diesel, no cam is needed, just a flywheel which would rub continually on the noise maker.

 

You also need to consider that the contact between the cam and the noise producing surface (didn't Triang Hornby use sandpaper?) is going to be a drag on the motor and may affect the performance.  In extreme cases it might lead to a surge of speed between chuffs, then the braking effect comes into play again

Edited May 20, 2018 by The Johnster

[Hroth]

Must admit that all my old Triang-Hornby locos with the chuff-chuff mechanism made a visit to the workshops ro have the cam on the axle moved sideways so it didn't strike the sounding bar.  Blissful silence!  The chuff-chuff sounds you made yourself were always much better.....

 

If you made one yourself, you have to bear in mind that as well as the cam on the axle and the friction spring, there is a resonating box in the tender to amplify the sound made by the action of the cam on the spring.

[Thunderforge]

Thanks for the ideas and feedback chaps, I shall post my results (good or bad) once I have got round to it.

I’m still cutting chassis and awaiting motors before any tests can happen.

 

I’ve never tried proper dcc with sound and smoke yet, and to be honest I’ve not been too impressed by what I’ve heard. There are some amazing things people have done out there but the budget rtr items are tinny and (as you say, Johnster,) staticky. No proper engine should go “shh shh shh”.

 

I like the idea of a continuously running diesel engine, and I wonder if using a vibrator with an echo chamber attached might work, which might also give it a little shuddering movement... unfortunately diesels are a little late for my preferred era, but worth throwing the idea out there. Of course it might be difficult to explain away your browsing history when looking for parts!

 

Personally I’ve always preferred the simpler mechanical solutions to better electrical solutions. As an example the electric window in my car has failed so I have to awkwardly reach around my open door to use multi storey car parks, seriously what was wrong with a hand winder?!

[cypherman]

Hi all,

Just out of interest the 2 locos Triang/Hornby used this chuffer system were the B12 and Albert Hall. Not sure if the chuffer made it onto the later Kneller Hall.

[DCB]

The "Chuffer" only "Chuffed" about once, maybe twice per revolution of the tender wheels. nothing like fast enough for the loco speed.  Had it been geared 4 to 1 to the driving wheels it would have been pretty good.  Better than some DCC sound in fact as DCC sound locos often sound like they are lifting 60 empties out of Cardiff when they are actually easing away with one autocoach.

 

I have been wondering if an axle driven sensor is the answer for DCC sound.  It can't be rocket science to have the sound mechanically linked to the rotation of the wheels, but none of the DCC sound I have heard sounds right. I guess it needs a different controller with acceleration, (loud exhaust)  constant speed (quieter exhaust) and coasting/braking   (no beats just hissing) to get the right effect

[Londontram]

Quote.

I have been wondering if an axle driven sensor is the answer for DCC sound. It can't be rocket science to have the sound mechanically linked to the rotation of the wheels, but none of the DCC sound I have heard sounds right. I guess it needs a different controller with acceleration, (loud exhaust) constant speed (quieter exhaust) and coasting/braking (no beats just hissing) to get the right effect

 

I'm wondering if you've hit the nail on the head here. Why just for DCC why not have a self contained unit that can be powered by the controller for DCC or by battery for DC that way you could still have all the hissing and wheel squeals on DC that you can on DCC the whole thing being controlled by an axle rotation sensor

Edited May 21, 2018 by Londontram

[Titan]

Seeing as a decoder knows how fast a motor is turning via the back emf, then synchronisation with speed should be dead easy without the need for any extra sensors. It could even measure the current draw and adjust for load too.

Edited May 21, 2018 by Titan

[Thunderforge]

We have the technology. With a computer controlling the vehicle speed it should be able to send co-ordinated sounds based on the change in speed (ie increase in speed = open regulator, slowing down a little = coasting, slowing down a lot = brake squeal, etc etc)

[MikeTrice]

Hi all,

Just out of interest the 2 locos Triang/Hornby used this chuffer system were the B12 and Albert Hall. Not sure if the chuffer made it onto the later Kneller Hall.

I am sure there was a Flying Scotsman as well. James May reassembled his.

 

A quick search has also identified the system fitted to Princess Victoria/Princess Royal and Hiawatha (using a Flying Scotsman tender painted black).

 

The feature was referred to as "Exhaust Steam Sound"

Edited May 21, 2018 by MikeTrice

[The Johnster]

Must admit that all my old Triang-Hornby locos with the chuff-chuff mechanism made a visit to the workshops ro have the cam on the axle moved sideways so it didn't strike the sounding bar.  Blissful silence!  The chuff-chuff sounds you made yourself were always much better.....

 

If you made one yourself, you have to bear in mind that as well as the cam on the axle and the friction spring, there is a resonating box in the tender to amplify the sound made by the action of the cam on the spring.

 

I make chuff chuff noises all the time during operating sessions, as well as vacuum pump, vacuum destroyed for brake test, and whistles.  Perhaps I should get out more, but it's much cheaper than DCC, and very much more realistic!

[kevinlms]

I make chuff chuff noises all the time during operating sessions, as well as vacuum pump, vacuum destroyed for brake test, and whistles.  Perhaps I should get out more, but it's much cheaper than DCC, and very much more realistic!

I've heard people use their voice to send bell codes. Ding.   Ding, ding, ding, ding.   Ding, ding.   Ding, Ding    Ding.   etc.

[MikeTrice]

Some photos of the mechanism fitted to the B12 tender.

 

The cam on the axle and the thin brass strip with striker surface:

 

The sound box fitted inside the tender:

 

The brass strip from below the footplate rises then cranks backwards and over the sound box with a final mounting on top:

 

 

Not the easiest to photograph.

 

[Thunderforge]

I’m sure it’s been drawn before, but...

 

[pauliebanger]

Quote.

I have been wondering if an axle driven sensor is the answer for DCC sound. It can't be rocket science to have the sound mechanically linked to the rotation of the wheels, but none of the DCC sound I have heard sounds right. I guess it needs a different controller with acceleration, (loud exhaust) constant speed (quieter exhaust) and coasting/braking (no beats just hissing) to get the right effect

 

I'm wondering if you've hit the nail on the head here. Why just for DCC why not have a self contained unit that can be powered by the controller for DCC or by battery for DC that way you could still have all the hissing and wheel squeals on DC that you can on DCC the whole thing being controlled by an axle rotation sensor

 

Don't know what you have been listening to to be making these type of comments.

 

All that you are suggesting and much more (progressive working brakes, selectable heavytrain/light engine configurations etc) is already available and has been for years on ZIMO DCC decoder steam projects, particularly those from Digitrains.

 

There are several ways to sync wheel rotation and chuff sounds, but the simplest is to use the decoder to count the rotations based on the BEMF measurements. Of course, it requires each installation to be set up correctly, but once done, it remains effective.

 

Digitrains' Jinty project has different exhaust sounds based on throttle (regulator) position (relative to actual road speed, so acceleration/cruising/drifting sounds are all accounted for) plus 4 different reverser positions.

 

It's unlikely that what I say will change any entrenched views on the quality DCC sound, and it's not the intention of my post to do so. But when set up and operated correctly, DCC sound, including steam sound, are far more comprehensive in range than is being given credit in this thread.

 

Best regards,

 

Paul

[sharris]

I make chuff chuff noises all the time during operating sessions, as well as vacuum pump, vacuum destroyed for brake test, and whistles.  Perhaps I should get out more, but it's much cheaper than DCC, and very much more realistic!

 

You should record them and program them into a DCC chip.

[Flying Pig]

I make chuff chuff noises all the time during operating sessions..

Yes, yes - and you'll be telling us next you sing in the Grumbly Town Choir.

[sharris]

I make chuff chuff noises all the time during operating sessions

 

Me too... but not always from my mouth. 

[Colin]

I used to have an Airfix 31 that sounded uncannily like a hard working diesel loco when I ran it at moderate speed- unfortunately this only happened in one direction, going the other way it was whisper quiet.

[Londontram]

Don't know what you have been listening to to be making these type of comments.

 

All that you are suggesting and much more (progressive working brakes, selectable heavytrain/light engine configurations etc) is already available and has been for years on ZIMO DCC decoder steam projects, particularly those from Digitrains.

 

There are several ways to sync wheel rotation and chuff sounds, but the simplest is to use the decoder to count the rotations based on the BEMF measurements. Of course, it requires each installation to be set up correctly, but once done, it remains effective.

 

Digitrains' Jinty project has different exhaust sounds based on throttle (regulator) position (relative to actual road speed, so acceleration/cruising/drifting sounds are all accounted for) plus 4 different reverser positions.

 

It's unlikely that what I say will change any entrenched views on the quality DCC sound, and it's not the intention of my post to do so. But when set up and operated correctly, DCC sound, including steam sound, are far more comprehensive in range than is being given credit in this thread.

 

Best regards,

 

Paul

Why is it when there's an interesting discussion going on theres always one who objects to someone else's general opinion or view and takes it personally.

 

Oh well another thread spoilt.... see you

[Steamport Southport]

I'm the last person that goes for "gimmicks". But if you've ever seen a layout doing DCC Sound properly then you would be impressed.

 

The two that were best for me were a small Southern Railway branch line layout with locomotives making all the right sounds, at all the right times. Including the clank of the Firehole door, coal being shovelled, brakes coming on/off, guards whistle, etc. It was more like watching a drama than a model railway.

 

The other was a large scale narrow gauge (O gauge?) USA logging layout with sound, smoke and lights. Even the locomotive's bell sound were clanking in time with the bell which was actually moving. They were so good that I thought the locomotives were live steam, they weren't.

 

Neither was too loud either. If I can find out what layouts they were I'll post the details.

 

 

 

Jason

[Steamport Southport]

Camel Quay was the Southern Region layout.

 

https://www.youtube.com/watch?v=Gfif7bgi474

 

https://www.youtube.com/watch?v=ZhN1_c5VtVM

 

 

 

I think we can safely say that is much better than a bit of sandpaper rubbing on an axle. 

 

Thread here. http://www.rmweb.co.uk/community/index.php?/topic/67862-camel-quay-a-north-cornwall-inspired-layout-in-4mm/page-1

 

 

 

Jason

[ejstubbs]

A quick search has also identified the system fitted to Princess Victoria/Princess Royal

 

It was certainly fitted on 6021 Princess Elizabeth in the early 1970s, along with synchrosmoke.  That was the loco that came in my "first proper train set", the Express Passenger Set (RS.609).  It also included two panelled and lined LMS coaches, which didn't seem to survive very long in production.

Edited May 27, 2018 by ejstubbs

[Colin]

Those coaches were the former Caledonian stock, think they were around for quite a while in various guises (they definitely appeared in GWR and Southern livery). I think they are still easy to come by secondhand, definitely seen a couple of LMS versions recently.