Freerails Home 
Home Search search Menu menu Not logged in - Login | Register
Freerails > Model Railroad Forums > Logging & Mining > Corrimal Colliery Incline

Because of non-railroad abuse of the site, new members MUST use their first names (at least) to join NO EXCEPTIONS!

Corrimal Colliery Incline
 Moderated by: oztrainz Page:  First Page Previous Page  1  2  3  4  5  6  7  8  9  ...  Next Page Last Page  
New Topic Reply Printer Friendly
 Rating:  Rating
AuthorPost
 Posted: Thu Jan 21st, 2016 10:24 am
  PMQuoteReply
31st Post
oztrainz
Super Moderator


Joined: Wed Apr 10th, 2013
Location: Unanderra, Australia
Posts: 733
Status: 
Online
Hi all again
Now to the saga of the skips. It has taken six years of on-and-off development to get coal skips that will:
- be dimensionally accurate in 1/43 scale in as many aspects as possible (excepting gauge)
- have reliable and robust inside bearings
- uncouple one at a time
- stay "attached" on a 1 in 4 (25%) grade either ascending unloaded or descending loaded with real coal
- be robust enough to handle being loaded and unloaded with real coal (this can be abrasive stuff)
- be able to be tipped and moved singly
- roll away on a 1 in 7 (14%) grade through reverse curves for a known amount of distance
- recouple into any skip when
- be as light as possible, yet track reliably through simulated colliery trackage that is buried to the rails.
- be detailed "enough" to pass our criteria for "detailed enough"
- be designed in a way that enables us to build a fleet of them as easily as possible (in full swing at Stage 3 over 70 skips will be required in the circuit between the mine and the incline)

There have been 7 major designs to get to a workable model skip design that met all of the above.

But first let's have a quick look at the prototype timber coal skips and "Burra" the locomotive that used to haul them at the Corrimal mine


The Mark 1 skips were fabricated from styrene and used Lima HO hook & loop couplings. These had oversize 10.6 mm diameter wheels and wouldn't roll freely on a 1 in 10 (10%) grade. So what did the Mark 1 coal skips look like?




Here they are on the Top End test rig and in action at https://www.youtube.com/watch?v=nXicbZs_dWQ

Underneath the Mark 1 skips looked like

This skip was one of the first ones fitted with DG couplings to replace the visually intrusive Lima couplings. Kaydee type couplings were ruled out because of interference from the high-powered magnets on the skip itself and the under-track chains.

The Mark 2 skips tried different underframe arrangement to get better rolling properties. These would roll easily on a 1 in 20 or 5% grade after they were dosed with graphite powder on the axles.

Mark 3 skips required the sourcing of 8 mm diameter 6-spoke wheels to match those on the 1:1 scale prototype skips. The Mark 3 skips used the Mark 2 underframe arrangement.

The Mark 1 skip with 10.6mm diameter wheels is painted brown on the left and the Mark 3 with 6-spoke 8 mm diameter wheels is in white styrene on the right.

The Mark 4 skip with 8 mm diameter wheels an DG Couplings fitted

The Mark 4 skips were the last fully styrene fabricated skip design. From the Mark 4 skip design things get interesting, but that can wait for the next post. Until the next time,

Last edited on Fri Feb 5th, 2016 10:58 pm by oztrainz



____________________
Regards,
John Garaty
Unanderra in oz
Back To Top

 Posted: Thu Jan 21st, 2016 11:33 am
  PMQuoteReply
32nd Post
Kitbash0n30
Registered


Joined: Mon Dec 10th, 2012
Location: Boonville, Missouri USA
Posts: 561
Status: 
Offline
Even in 1:43 scale, 8mm wheels are little wheels, maybe 14 inches in real life?



____________________
See y'all later, Forrest.
Screw the rivets, I'm building for atmosphere
Back To Top

 Posted: Thu Jan 21st, 2016 12:05 pm
  PMQuoteReply
33rd Post
NevadaBlue
Registered


Joined: Mon Apr 7th, 2014
Location: Under The Blue Nevada Sky, Nevada USA
Posts: 705
Status: 
Offline
Nice work John. I'm guessing that the Mk 4 skips will be printed? Watching with interest.



____________________
Ken

Back To Top

 Posted: Thu Jan 21st, 2016 03:36 pm
  PMQuoteReply
34th Post
oztrainz
Super Moderator


Joined: Wed Apr 10th, 2013
Location: Unanderra, Australia
Posts: 733
Status: 
Online
Kitbash0n30 wrote:
Even in 1:43 scale, 8mm wheels are little wheels, maybe 14 inches in real life?

Hi Forrest & all,
The prototype skips actually have 12" diameter wheels under them, which in 1/43 scale is 7 mm diameter wheels. To get the 6-spokes, 8 mm was the smallest the wheel maker could do at the time, so 8mm diameter it was... These were a special order a few years ago and are now part of the regular KB Scale range http://www.kbscale.com/wheels.html Thanks to Dave at KB Scale we have good wheels that look good.

We did look at using N-scale wheels to get the diameter early on, but the 6-spokes weren't available. The rail choice was to stay with Peco code 100 rail because "It works" and all our test rigs were done with this rail which is readily available. The HO RP25 profile treads from KB Scale behave themselves very well on this track.



____________________
Regards,
John Garaty
Unanderra in oz
Back To Top

 Posted: Thu Jan 21st, 2016 04:35 pm
  PMQuoteReply
35th Post
Kitbash0n30
Registered


Joined: Mon Dec 10th, 2012
Location: Boonville, Missouri USA
Posts: 561
Status: 
Offline
oztrainz wrote: The HO RP25 profile treads from KB Scale behave themselves very well on this track.Makes sense. And looking at that, the 8mm wheels give just a hair more flange arc inside the rails to help keep the cars where they belong, which may or may not be that much of a factor, but I was just reading something the other day about flange drag on curves being related to wheel diameter and wheelbase.



____________________
See y'all later, Forrest.
Screw the rivets, I'm building for atmosphere
Back To Top

 Posted: Thu Jan 21st, 2016 05:33 pm
  PMQuoteReply
36th Post
Tramcar Trev
Registered


Joined: Sat Mar 16th, 2013
Location: Gordon ACT, Australia
Posts: 418
Status: 
Offline
Kitbash0n30 wrote:
oztrainz wrote: The HO RP25 profile treads from KB Scale behave themselves very well on this track.Makes sense. And looking at that, the 8mm wheels give just a hair more flange arc inside the rails to help keep the cars where they belong, which may or may not be that much of a factor, but I was just reading something the other day about flange drag on curves being related to wheel diameter and wheelbase.

I agree, a lot more in "flanges" than meets the eye. I reprofiled the flanges on my Bachmann trams to get them to stay on the track, simply by radiusing the edge of the flange made a world of difference. I think it stopped climbing on the rail edge on sharpe curves that was happening with the razor sharpe edge that Mr Bachmann puts on his flanges....



____________________
There once was a man who said Damn!!
I perceive with regret that I am
A creature that moves
in predestinate groves
I'm not a Bus, I'm a tram
Back To Top

 Posted: Fri Feb 5th, 2016 11:53 pm
  PMQuoteReply
37th Post
oztrainz
Super Moderator


Joined: Wed Apr 10th, 2013
Location: Unanderra, Australia
Posts: 733
Status: 
Online
Hi all again,
OK so where was we? That's right, we were talking coal skips :bg:

oztrainz wrote:
Hi all again
Now to the saga of the skips. It has taken six years of on-and-off development to get coal skips...

The Mark 4 skips were the last fully styrene fabricated skip design. From the Mark 5 skip design things get interesting, but that can wait for the next post. Until the next time,


So here we go - resuming with a photo of a Mark 4 skip from styrene with 8mm diameter wheels, but without couplings


The Mark 5 coal skips. The Mark 5 skips were the only attempt we made at a full 3D print. For comparison a 3D-printed Mark 5 followed by the all-styrene Mark 4 skip.

The Mark 5 skips were done with a fully detailed underframe with correct bolt and bearing details and with a correctly dimensioned coal box with all metalwork details 3D printed onto the interior and exterior of the coal box.

and under

The bearings on this version were like the prototype - they only extended to 1/2 of the axle diameter. We had problems keeping the axles in the bearings.So that needed to be modified.
There were only 3 of these produced. All 3 exhibited the striations up the side. This was disappointing quality wise and it was more obvious once the skips were painted. At over $20 each for a small skip and possibly over 70 of them required, a cheaper option was required.

The cheaper option was to simply print the underframe and use other techniques to produce the coal bin part of the skip. This resulted in Mark 6 underfram and resin cast (by us) coal box bodies. The Mark 6 underfame design was modified to have a retaining ring added to help hold the magnet. The Mark 6 underframe simply extended the depth of the sides on the bearing to help retain the wheels.

A couple of other problems emerged with the Mark 6 that prevented a "dead-accurate" underframe from the Mark 5 being used. Boltheads at each end under the underframe prevented the couplings from sitting flat. So they had to go. And the small size of the bearing sides needed beefing up. Which led to the final underframe design - the Mark 7. For comparison purposes the next 2 photos are the Mark 6 underframe followed by the final Mark 7 design.




The key differences with the Mark 7 are the hollowed out magnet retainer and the removal of the central frame timber (to save on 3D printing costs) and beefed-up bearings with a 0.5mm printed hole for the axle retaining wires. A look under a fully assembled Mark 7 skip underframe

The axle retaining wires only have to support the weight of the the wheels and axles when the skip is lifted off the rails. A few puffs of graphite powder into the open bottom of the bearings ensure that these skips roll very well.

A roster shot of some Mark 7 skips in the build process

See, I told you we needed a "few" coal skips. This will be about 1/2 of the final roster. This photo was in November 2013. Wagons behind the green locomotive are on wheels.

and to close out - a photo of a couple of Mark 7 skips loaded with coal, this time, right way up. :bg:


That ought to do for coal skip designing and building. Next up - track laying on the incline.



____________________
Regards,
John Garaty
Unanderra in oz
Back To Top

 Posted: Sat Feb 6th, 2016 12:18 am
  PMQuoteReply
38th Post
Kitbash0n30
Registered


Joined: Mon Dec 10th, 2012
Location: Boonville, Missouri USA
Posts: 561
Status: 
Offline
Ladies and gentlemen, what we have here is a serious case of product design evolution.
Dang, and I thought the 15 pulpwood cars for the HO and the 16 ore tippers by HLW for the G, which I want to have by year's end, are a lot of cars.
Just counted 73 skips in that photo.

Last edited on Sat Feb 6th, 2016 12:20 am by Kitbash0n30



____________________
See y'all later, Forrest.
Screw the rivets, I'm building for atmosphere
Back To Top

 Posted: Sat Feb 6th, 2016 03:49 am
  PMQuoteReply
39th Post
Si.
Super Moderator


Joined: Thu Feb 23rd, 2012
Location: London
Posts: 3288
Status: 
Offline
:moose::moose::moose::moose::moose: ... etc. x73 of !

Cheers.

Si.



____________________

' Mysterious Moose Mountain ' - 1:35n2 - pt.II
http://www.freerails.com/view_topic.php?id=7318&forum_id=17&page=1

' M:R:W Motor Speedway !!! ' - 1:32 Slotcar Racing Layout
http://www.slotforum.com/forums/index.php?showtopic=59295&st=0&a
Back To Top

 Posted: Sat Feb 6th, 2016 04:35 am
  PMQuoteReply
40th Post
Tramcar Trev
Registered


Joined: Sat Mar 16th, 2013
Location: Gordon ACT, Australia
Posts: 418
Status: 
Offline
Do you know what caused the striations up the side in the earlier printed versions?
Mate you seriously need to get your own 3D printer and recoup your costs buy selling those skips on ebay...
They remind me very much of the ones we unearthed in Balmain that presumably were part of the Colluiery there...



____________________
There once was a man who said Damn!!
I perceive with regret that I am
A creature that moves
in predestinate groves
I'm not a Bus, I'm a tram
Back To Top


 Current time is 08:58 am
Page:  First Page Previous Page  1  2  3  4  5  6  7  8  9  ...  Next Page Last Page  

Freerails > Model Railroad Forums > Logging & Mining > Corrimal Colliery Incline
Top



UltraBB 1.172 Copyright © 2007-2016 Data 1 Systems