Mike Garwood
Western Thunderer
Nick
If any of this stuff helps anyone then I am truly thrilled.
If and when you get under way let me know.
Mike
Mike G's Workspace.
- Thread starter Mike Garwood
- Start date
If any of this stuff helps anyone then I am truly thrilled.
If and when you get under way let me know.
Mike
Nick Rogers
Western Thunderer
Thank you, sir! I will do.
I’m currently restoring/rebuilding a brass Chivers SR PMV, which came from the estate of a late model maker. Once that is complete, I suspect some chassis will be on the cards.
Mike Garwood
Western Thunderer
Work has begun on the GWR 9" pressed steel bogies. These are from Rumney models, construction notes are on line - as usual- these are always worth reading, even if you don't follow them. There are some very elegant design aspects that Justin has worked into the bogie ends.
The etches form an elegant design that incorporates secondary suspension. Having built a lot of the Bill Bedford sprung bogies, which is what I settled on for all my coaching stock, these do not have a secondary suspension system and as yet I cannot fault their performance. I believe that there are / where modifications available to add secondary suspension to Bills design. I've never found these to have been necessary.
This being the case I dispensed with the secondary suspension that was offered on Justin's design. This does not mean that the bogie design has been compromised, merely altered to suit my needs.
I just opened out the holes for the SS and pushed thru some 0.6 mm wire and then soldered that solid to the chassis. This renders the SS as redundant. Now the only difference is that Justins bogies have 4 separate springs and Bill's has 2. Personally, I can find no difference in their performance. In terms of appearance (before cosmetic sides are attached) then Justins' design certainly has the edge. So why the change? Well since the sudden demise of the much missed Eileens the ability to purchase stocks has - I hope - temporarily dried up.
Both Mousa and Rumney models offer brakes to be added to the chassis. I've never found the need to put brakes on the chassis as most cosmetic sides obliterate them from view and how many of us look for brakes on coaches trundling along?
An excellent product and a pair can be easily built in an evenings modeling. When I look back at was available when I first started building coaches some 30 years ago, we have been fortunate to have had 2 visionaries who have developed a sturdy and reliable method of springing.
And in more good news, SWMBO is off on her travels at the end of November...
Stay safe
Mike
The etches form an elegant design that incorporates secondary suspension. Having built a lot of the Bill Bedford sprung bogies, which is what I settled on for all my coaching stock, these do not have a secondary suspension system and as yet I cannot fault their performance. I believe that there are / where modifications available to add secondary suspension to Bills design. I've never found these to have been necessary.
This being the case I dispensed with the secondary suspension that was offered on Justin's design. This does not mean that the bogie design has been compromised, merely altered to suit my needs.
I just opened out the holes for the SS and pushed thru some 0.6 mm wire and then soldered that solid to the chassis. This renders the SS as redundant. Now the only difference is that Justins bogies have 4 separate springs and Bill's has 2. Personally, I can find no difference in their performance. In terms of appearance (before cosmetic sides are attached) then Justins' design certainly has the edge. So why the change? Well since the sudden demise of the much missed Eileens the ability to purchase stocks has - I hope - temporarily dried up.
Both Mousa and Rumney models offer brakes to be added to the chassis. I've never found the need to put brakes on the chassis as most cosmetic sides obliterate them from view and how many of us look for brakes on coaches trundling along?
An excellent product and a pair can be easily built in an evenings modeling. When I look back at was available when I first started building coaches some 30 years ago, we have been fortunate to have had 2 visionaries who have developed a sturdy and reliable method of springing.
And in more good news, SWMBO is off on her travels at the end of November...
Stay safe
Mike
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Yorkshire Dave
Western Thunderer
I think it all depends on scale, period, the bogie type you're modelling and individual choice. Older bogies up to and including the BR mark 1 (including Commonwaelth) have so much clutter on the outside such as tie rods and footboard the brakes can be lost in the detail. With newer, lighter constructed bogies the brake detail becomes conspicuous by it's absence, even on the B4 where the brakes are visible on the outer ends. Today the majority, if not all, tend to be disc brakes between the wheels.
timbowales
Western Thunderer
As an ex-insider it has long been known that moving to disc brakes, whilst improving stopping distances in "normal" conditions, got rid of the "wheel cleaning" effects of conventional tread brakes. Unfortunately things have been exacerbated by the uncontrolled growth of lineside vegetation! More trees = more leaves = more gunge on the rail heads = less grip
I had always assumed several factors had contributed to making autumn leaves a bigger problem. Perhaps the major one being the line-side vegetation. There are a lot more trees on cutting/embankment sides that there used to be. Just compare a few ‘then and now’ photographs. In some regions at least there has been a trend to wetter autumns (and drier summers) over several decades. Trains, certainly powered vehicles, weigh less and have lower axle loads.
Captain Kernow
Western Thunderer
Certainly the fact that my former employers switched to Liquid Growmore as a weedkiller some years ago, didn't help.
simond
Western Thunderer
It’s certainly true that tread brakes cleaned the wheels - my uncertainty is whether that wheel cleaning also cleaned the railhead.
OK, here we go!
There are a few issues to consider: suspension design, brake design and contamination.
Prior to the better understanding of wheel-rail interaction that arose during the development of the APT, bogie design was largely empirical and evolutionary. If you consider something like a first generation EMU they didn't ride particularly well and a lot of energy was used at the wheel rail interface just keeping the train on the track. The result was fairly rapid wheel wear. The positive consequence of this is that the energy helped keep the wheels clean. When you move onto something like the class 158/9 they curve very well and not much energy is wasted at the interface. The downside is that the treads are not cleaned - but the wheel life on modern stock is significantly longer than on older trains.
Although suspension design is important, the difference between tread braking and disc braking has more effect on tread cleaning. Tread braking was normally done by cast iron brake blocks which are very effective at low speeds. However, cast iron blocks give off a lot of dust - hence the need for strong cleaners in wash plants - and have very short life as speeds increase. The 100mph Clacton EMUs had to have a new set of brake blocks every 2 days! Disc brakes are more effective at dissipating higher energies so when the 90mph class 158s were introduced they were/are fitted with disc brakes. Disc brakes were also fitted to lower speed units - classes 313 onwards and 507 onwards. At the same time braking control was also changed from what had effectively been an analogue system - vacuum or EP - to a digital system where only three steps of brake control (7 in HST's) were available to the driver. The new units were not welcomed by the drivers and Signals Passed At Danger were a frequent occurrence. To prevent wheel slide Wheel Slide Protection (WSP) systems are fitted to disc braked stock. The early systems were very crude and simply dumped the brake cylinder pressure to release the brakes. Incidentally, HST Power Cars are fitted with both disc brakes (80% of brake force) and tread brakes (20%) with the tread brakes there to scrub the tread to ensure sufficient adhesion for traction.
BR Research did a lot of work with the Tribometer train to understand adhesion. It was found that by allowing the wheelset to creep - rotate at a speed slightly less than synchronous speed - the energy generated at the wheel-rail interface was sufficient to induce cleaning of both wheel and rail (thereby answering the original question posed above) and increasing the available adhesion. A clever chap called John Rosser came up with an idea for using the adhesion algorithms in a hybrid device for testing WSP systems. A computer input wheel speeds into the WSP that was connected to a series of pipes representing the vehicle pneumatics. Under test the whole array would sit there hissing and farting as the WSP did its job. It became known as Rosser's Organ and was used by various WSP suppliers to tune their devices to different vehicle configurations. It survived privatisation but I am not sure where it is now. Modern WSP systems aim to control brake cylinder pressure so that wheels creep and improve adhesion.
Leaf fall is undoubtedly the most serious contaminant as affects all stock both disc and tread braked. One of the longest ever signal overruns was on the SR involving a 12 car block braked train, so the idea that it is only short disc braked trains that are affected is wrong. However, in general short trains are more likely to have problems. Even so, Japanese Shinkanshen 12 car trains are arranged so that the outer 2 cars brake at 80% of the desired rate, the central 4 at 120% and the other 4 at 100%. In this way the most heavily braked cars are likely to experience better adhesion than the leading cars whose braking will clean the rails.
Problems with 158s led BR Research to develop the one shot sander - a one use fire extinguisher that blasted sand not foam when selected. This was fitted to the units for a while but removed later. The Rail Safety and Standards Board - a body that is funded to reinvent the wheel - has come up with ideas for proportional sanding. Sand certainly helps.
The real answer to leaf fall would be to remove the vegetation that has been allowed to flourish since the end of steam. Unfortunately, as well as the response from environmentalists - and those in houses with arboreal sound barriers between them and the track - removing trees could result in stability problems in embankments, so we will have to continue with expensive rail head treatment trains.
There are a few issues to consider: suspension design, brake design and contamination.
Prior to the better understanding of wheel-rail interaction that arose during the development of the APT, bogie design was largely empirical and evolutionary. If you consider something like a first generation EMU they didn't ride particularly well and a lot of energy was used at the wheel rail interface just keeping the train on the track. The result was fairly rapid wheel wear. The positive consequence of this is that the energy helped keep the wheels clean. When you move onto something like the class 158/9 they curve very well and not much energy is wasted at the interface. The downside is that the treads are not cleaned - but the wheel life on modern stock is significantly longer than on older trains.
Although suspension design is important, the difference between tread braking and disc braking has more effect on tread cleaning. Tread braking was normally done by cast iron brake blocks which are very effective at low speeds. However, cast iron blocks give off a lot of dust - hence the need for strong cleaners in wash plants - and have very short life as speeds increase. The 100mph Clacton EMUs had to have a new set of brake blocks every 2 days! Disc brakes are more effective at dissipating higher energies so when the 90mph class 158s were introduced they were/are fitted with disc brakes. Disc brakes were also fitted to lower speed units - classes 313 onwards and 507 onwards. At the same time braking control was also changed from what had effectively been an analogue system - vacuum or EP - to a digital system where only three steps of brake control (7 in HST's) were available to the driver. The new units were not welcomed by the drivers and Signals Passed At Danger were a frequent occurrence. To prevent wheel slide Wheel Slide Protection (WSP) systems are fitted to disc braked stock. The early systems were very crude and simply dumped the brake cylinder pressure to release the brakes. Incidentally, HST Power Cars are fitted with both disc brakes (80% of brake force) and tread brakes (20%) with the tread brakes there to scrub the tread to ensure sufficient adhesion for traction.
BR Research did a lot of work with the Tribometer train to understand adhesion. It was found that by allowing the wheelset to creep - rotate at a speed slightly less than synchronous speed - the energy generated at the wheel-rail interface was sufficient to induce cleaning of both wheel and rail (thereby answering the original question posed above) and increasing the available adhesion. A clever chap called John Rosser came up with an idea for using the adhesion algorithms in a hybrid device for testing WSP systems. A computer input wheel speeds into the WSP that was connected to a series of pipes representing the vehicle pneumatics. Under test the whole array would sit there hissing and farting as the WSP did its job. It became known as Rosser's Organ and was used by various WSP suppliers to tune their devices to different vehicle configurations. It survived privatisation but I am not sure where it is now. Modern WSP systems aim to control brake cylinder pressure so that wheels creep and improve adhesion.
Leaf fall is undoubtedly the most serious contaminant as affects all stock both disc and tread braked. One of the longest ever signal overruns was on the SR involving a 12 car block braked train, so the idea that it is only short disc braked trains that are affected is wrong. However, in general short trains are more likely to have problems. Even so, Japanese Shinkanshen 12 car trains are arranged so that the outer 2 cars brake at 80% of the desired rate, the central 4 at 120% and the other 4 at 100%. In this way the most heavily braked cars are likely to experience better adhesion than the leading cars whose braking will clean the rails.
Problems with 158s led BR Research to develop the one shot sander - a one use fire extinguisher that blasted sand not foam when selected. This was fitted to the units for a while but removed later. The Rail Safety and Standards Board - a body that is funded to reinvent the wheel - has come up with ideas for proportional sanding. Sand certainly helps.
The real answer to leaf fall would be to remove the vegetation that has been allowed to flourish since the end of steam. Unfortunately, as well as the response from environmentalists - and those in houses with arboreal sound barriers between them and the track - removing trees could result in stability problems in embankments, so we will have to continue with expensive rail head treatment trains.
Mike Garwood
Western Thunderer
The 4 sets of pressed steel bogies are now completed and wheeled. No fuss in building them at all. (Rumney Models...of course)
The first coach to go into the production line is this one:
It'll be completed onto BR Maroon - as will the rest of the M set. These coaches have to be ready for paint in March next year, as that's when SWMBO is off on a weeks holiday. So plenty of time, if I can complete one per month.
I must have robbed this kit of it's chassis as there wasn't one in the box, one is winging it's way from Comet and I'm going to have to order some more detail packs as well for the dreaded hinges.
Today saw the sides almost completed, hinges are in, as are internal windows and door stops. I can't make up my mind whether to add the door handles and grab handles now or wait until I've finished lining the coach.
Not the worlds greatest photo thanks to the glare from my lamp.
Anyway, the fight has just begun.
Last Friday I went to see the Aussy Pink Floyd in Cardiff, fourth time I've been to see them, they did not disappoint, superb, sang my heart out with them! My son and son in law came with, so a little bit of lager and Southern comfort was consumed. Sunday was Newport MRS open day, great fun day, put it in your diaries for next year. You can drive the layouts on show and chat to all and sundry. I was hosting the Scale4 bit and had a great time chatting with a lot of interested modelers and a few passing friends who popped in during the day. Having some time with like minded souls is so refreshing.
Stay safe
Mike.
The first coach to go into the production line is this one:
It'll be completed onto BR Maroon - as will the rest of the M set. These coaches have to be ready for paint in March next year, as that's when SWMBO is off on a weeks holiday. So plenty of time, if I can complete one per month.
I must have robbed this kit of it's chassis as there wasn't one in the box, one is winging it's way from Comet and I'm going to have to order some more detail packs as well for the dreaded hinges.
Today saw the sides almost completed, hinges are in, as are internal windows and door stops. I can't make up my mind whether to add the door handles and grab handles now or wait until I've finished lining the coach.
Not the worlds greatest photo thanks to the glare from my lamp.
Anyway, the fight has just begun.
Last Friday I went to see the Aussy Pink Floyd in Cardiff, fourth time I've been to see them, they did not disappoint, superb, sang my heart out with them! My son and son in law came with, so a little bit of lager and Southern comfort was consumed. Sunday was Newport MRS open day, great fun day, put it in your diaries for next year. You can drive the layouts on show and chat to all and sundry. I was hosting the Scale4 bit and had a great time chatting with a lot of interested modelers and a few passing friends who popped in during the day. Having some time with like minded souls is so refreshing.
Stay safe
Mike.
Dangerous Davies
Western Thunderer
Great to see you on Sunday Mike and to reminisce about the good old days at “The Orb”.
Mike Garwood
Western Thunderer
It's been a nice couple days, really mild weather etc, etc...which is why I've been hiding in my study working on this coach. Ends have been detailed, but not completed.
Today I chopped up the roof to size and it's a good job I've got spares because I cut the first too short! And in the process of drilling the holes for the roof details used every single small sized drill from 0.4 to 0.6 mm drills that I had as spares. So much for 'don't spend anymore money on railways as Christmas is coming!'
Coming along nicely, it's been fun.
Stay safe
Mike
(heading to ebay)
Today I chopped up the roof to size and it's a good job I've got spares because I cut the first too short! And in the process of drilling the holes for the roof details used every single small sized drill from 0.4 to 0.6 mm drills that I had as spares. So much for 'don't spend anymore money on railways as Christmas is coming!'
Coming along nicely, it's been fun.
Stay safe
Mike
(heading to ebay)
Mike Garwood
Western Thunderer
It's been an incredibly busy day...
At 09:45 SWMBO departed the premises for the weekend. No, the dinning room is still full of the Grandchildren's Arts & Crafts stuff. First off a long visit to my dentist for an hour and a half. On my return I have put up 2 new 7 ft shelves in the study, which means I have my computer desk back! And the over flowing library is no longer in front of my desktop. And the big plus is that I have my mini drill now on my work bench, instead of a box.
D121.
A fair bit of progress from the last pictures as you'll see. I won't list it all off as that's just boring.
Still more detailing to finish off the ends and then onto the interior.
Have a great weekend all and stay safe.
Mike
At 09:45 SWMBO departed the premises for the weekend. No, the dinning room is still full of the Grandchildren's Arts & Crafts stuff. First off a long visit to my dentist for an hour and a half. On my return I have put up 2 new 7 ft shelves in the study, which means I have my computer desk back! And the over flowing library is no longer in front of my desktop. And the big plus is that I have my mini drill now on my work bench, instead of a box.
D121.
A fair bit of progress from the last pictures as you'll see. I won't list it all off as that's just boring.
Still more detailing to finish off the ends and then onto the interior.
Have a great weekend all and stay safe.
Mike