8-10 coaches & a 1:50 incline
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My layout is designed for 8-coach trains. It has lower and upper levels on one side, to accomodate hidden storage sidings below and a scenic run above. I ran some tests with Hornby Bulleids, King Arthurs, standard 4s and 5s etc. and found I needed a gradient no steeper than 1 in 70 for these. The King Arthurs would only take 8 Bachmann MK1s up this gradient after the coaches' weights had been removed - otherwise it was only 6. The gradients are all on 36-inch radius curves also, which doesn't help.
No problems with diesels I found - Heljan class 33 would take 12 without blinking. Likewise Bachmann 9Fs.
I'd suggest you do some tests with your intended locos and coaches and see what the results are, taking into account curves as well. I also tested both through running as well as starting from the bottom of the gradient and half-way up. Some locos would reach the top if given a good run at it, but wouldn't start on the gradient.
No problems with diesels I found - Heljan class 33 would take 12 without blinking. Likewise Bachmann 9Fs.
I'd suggest you do some tests with your intended locos and coaches and see what the results are, taking into account curves as well. I also tested both through running as well as starting from the bottom of the gradient and half-way up. Some locos would reach the top if given a good run at it, but wouldn't start on the gradient.
QUOTE (oitoitoi @ 28 Jan 2009, 15:06) <{POST_SNAPBACK}>Hey guys, in the design process and am wondering would a new hornby loco (e.g. A4, A3, 8F) with 8 to 10 coaches be able to deal with a 1:50 incline?
Only if you add weight. The only RTR OO steamer I would bet money on taking 10 coaches up that gradient would be Bachmann's 9F. The loco weighs about 500g and as that is virtually all on the coupled wheels, it has the necessary grunt. The Hornby Britannia and Bachmann A4 might just about do it, also a decent weight. Plenty of room in the A3 and A4 you mention to get them up to a similar weight. The 8F is a real problem, difficult to get enough weight into.
RFS advice to do some trials for yourself strongly seconded.
Only if you add weight. The only RTR OO steamer I would bet money on taking 10 coaches up that gradient would be Bachmann's 9F. The loco weighs about 500g and as that is virtually all on the coupled wheels, it has the necessary grunt. The Hornby Britannia and Bachmann A4 might just about do it, also a decent weight. Plenty of room in the A3 and A4 you mention to get them up to a similar weight. The 8F is a real problem, difficult to get enough weight into.
RFS advice to do some trials for yourself strongly seconded.
Thanks for the advice guys, will definitely have to do some trials, not really keen on adding weight to the locos though so will try and work out a way to get a shallower gradient. Does weight put much more strain on the loco motors? Has anyone had any experience of locos becoming 'worn out' through use?
QUOTE (dwb @ 28 Jan 2009, 19:17) <{POST_SNAPBACK}>My experience with current Hornby pacifics is similar to RFS. Six coaches max for 36 inch curve on 1:48 gradient. I'm hoping 7 might be possible if the loco gets a good run at it.
David
Is that a 36" radius or diameter curve? I was planning for minimum 18" radius curves so I'm hoping it's the former!
I think I can get it to 1:57 or possibly even 1:62 with some precise woodworking, any idea if that could handle 8-10 much better? The locos would be hitting the up inclines at top speed and wouldn't have to stop on them so restarting shouldn't be an issue.
Does anyone know the precise height of a hornby A4, A3 or 8F......I can't find a ruler, not even a tape measure...really need to tidy the house...
QUOTE (dwb @ 28 Jan 2009, 19:17) <{POST_SNAPBACK}>My experience with current Hornby pacifics is similar to RFS. Six coaches max for 36 inch curve on 1:48 gradient. I'm hoping 7 might be possible if the loco gets a good run at it.
David
Is that a 36" radius or diameter curve? I was planning for minimum 18" radius curves so I'm hoping it's the former!
I think I can get it to 1:57 or possibly even 1:62 with some precise woodworking, any idea if that could handle 8-10 much better? The locos would be hitting the up inclines at top speed and wouldn't have to stop on them so restarting shouldn't be an issue.
Does anyone know the precise height of a hornby A4, A3 or 8F......I can't find a ruler, not even a tape measure...really need to tidy the house...
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I am guessing that the mass required to create the wheel to track traction (friction) needed to actually damage the motor would be a number of times more than what you need for creating the necessary traction to pull your coaches up the incline.
One way to do it would be experiment to destruction (YEAH!) and apply known masses to a loco and measure tractive effort. Could be done on a rolling road I imagine with a load gauge being pulled against to measure effective tractive force. Put the whole device on a scale and measure the mass changes.
Put it on a live web cam so we can all tune in to see how it is going too.
One way to do it would be experiment to destruction (YEAH!) and apply known masses to a loco and measure tractive effort. Could be done on a rolling road I imagine with a load gauge being pulled against to measure effective tractive force. Put the whole device on a scale and measure the mass changes.
Put it on a live web cam so we can all tune in to see how it is going too.
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one of the things to bear in mind is that there is greater stress on the locomotive climbing a curve at 1:50 compared to climbing a straight section at 1:50.
Is 1:50 a 2% grade? ie you are climbing 1 inch every 50 inches?
Cheers
John
Is 1:50 a 2% grade? ie you are climbing 1 inch every 50 inches?
Cheers
John
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9,983 Posts
*** Are you sure about that 18" radius - any loco bigger than a shunter or rolling stock longer than a 4 wheel wagon will look truly terrible on a radius that small.
You will also really increase friction to the point that you nearly double the load - I sincerely doubt whether you will get 4 or at best 5 coaches up a grade at 18" radius if 8 will go up the same grade at 36".
Can you "split the grade"?
In otherwords have one line go down as the other goes up - that way you will halve the gradient to about 1 in 100 and there will be few problems ever, even with a tight radius.
You could also use STEEL rail on the gradients - this will make a big difference to what can be handled - adding about 1/3 more capability with the same loco without slipping!
C&L do steel OO track in Bullhead rail.... or flatbotton code 82 in steel
Adding weight is the only other answer really... and that will still not help that much if the curves are too tight!
Richard
QUOTE (oitoitoi @ 29 Jan 2009, 09:08) <{POST_SNAPBACK}>Thanks for the advice guys, will definitely have to do some trials, not really keen on adding weight to the locos though so will try and work out a way to get a shallower gradient. Does weight put much more strain on the loco motors? Has anyone had any experience of locos becoming 'worn out' through use? Is that a 36" radius or diameter curve? I was planning for minimum 18" radius curves so I'm hoping it's the former!
I think I can get it to 1:57 or possibly even 1:62 with some precise woodworking, any idea if that could handle 8-10 much better? The locos would be hitting the up inclines at top speed and wouldn't have to stop on them so restarting shouldn't be an issue.
Does anyone know the precise height of a hornby A4, A3 or 8F......I can't find a ruler, not even a tape measure...really need to tidy the house...
You will also really increase friction to the point that you nearly double the load - I sincerely doubt whether you will get 4 or at best 5 coaches up a grade at 18" radius if 8 will go up the same grade at 36".
Can you "split the grade"?
In otherwords have one line go down as the other goes up - that way you will halve the gradient to about 1 in 100 and there will be few problems ever, even with a tight radius.
You could also use STEEL rail on the gradients - this will make a big difference to what can be handled - adding about 1/3 more capability with the same loco without slipping!
C&L do steel OO track in Bullhead rail.... or flatbotton code 82 in steel
Adding weight is the only other answer really... and that will still not help that much if the curves are too tight!
Richard
QUOTE (oitoitoi @ 29 Jan 2009, 09:08) <{POST_SNAPBACK}>Thanks for the advice guys, will definitely have to do some trials, not really keen on adding weight to the locos though so will try and work out a way to get a shallower gradient. Does weight put much more strain on the loco motors? Has anyone had any experience of locos becoming 'worn out' through use? Is that a 36" radius or diameter curve? I was planning for minimum 18" radius curves so I'm hoping it's the former!
I think I can get it to 1:57 or possibly even 1:62 with some precise woodworking, any idea if that could handle 8-10 much better? The locos would be hitting the up inclines at top speed and wouldn't have to stop on them so restarting shouldn't be an issue.
Does anyone know the precise height of a hornby A4, A3 or 8F......I can't find a ruler, not even a tape measure...really need to tidy the house...
QUOTE (oitoitoi @ 29 Jan 2009, 00:08) <{POST_SNAPBACK}>..Does weight put much more strain on the loco motors? Has anyone had any experience of locos becoming 'worn out' through use? ..
In the case of Hornby they use that same 'black can' motor in all their recent releases, including diesel types weighing up to 600g. So you are quite safe up to that weight: provided the loco can still slip its' wheels when held back, the motor will be OK. I wear locos out: it usually takes fifteen years of an hour of operation practically every day, and it is usually something other than the motor that gives up. Motors are discrete easy to replace components in any case.
QUOTE ..Is that a 36" radius or diameter curve? I was planning for minimum 18" radius curves so I'm hoping it's the former! ..
Ah. The drag from an 18" radius curve is about as bad as a 1 in 30, by the time you have vehicles occupying the full 180 degrees. Larger radii impose smaller loads, and are also more reliable if running long trains. A big risk with small radius curves and long trains is a derailment as the vehicles pull across the chord of the curve, often referred to as 'stringlining'.
QUOTE ..I think I can get it to 1:57 or possibly even 1:62 with some precise woodworking, any idea if that could handle 8-10 much better? The locos would be hitting the up inclines at top speed and wouldn't have to stop on them so restarting shouldn't be an issue. ..
Make them as easy as possible. Richard's suggestion of sharing the gradients between rising and falling lines is a good technique. If you can get the gradient to 1 in 100 there are relatively few problems - most 'level' layouts actually have a gradient of this order present.
QUOTE ..Does anyone know the precise height of a hornby A4, A3 or 8F..
The UK loading gauge permits a maximum height just over 13 feet, and all these designs were built to that height. So that's a fraction over 52mm if the model maker gets it right (and it is right on the current Hornby A4, A3 and 8F), allow a minimum of 60mm height clearance over rail top.
In the case of Hornby they use that same 'black can' motor in all their recent releases, including diesel types weighing up to 600g. So you are quite safe up to that weight: provided the loco can still slip its' wheels when held back, the motor will be OK. I wear locos out: it usually takes fifteen years of an hour of operation practically every day, and it is usually something other than the motor that gives up. Motors are discrete easy to replace components in any case.
QUOTE ..Is that a 36" radius or diameter curve? I was planning for minimum 18" radius curves so I'm hoping it's the former! ..
Ah. The drag from an 18" radius curve is about as bad as a 1 in 30, by the time you have vehicles occupying the full 180 degrees. Larger radii impose smaller loads, and are also more reliable if running long trains. A big risk with small radius curves and long trains is a derailment as the vehicles pull across the chord of the curve, often referred to as 'stringlining'.
QUOTE ..I think I can get it to 1:57 or possibly even 1:62 with some precise woodworking, any idea if that could handle 8-10 much better? The locos would be hitting the up inclines at top speed and wouldn't have to stop on them so restarting shouldn't be an issue. ..
Make them as easy as possible. Richard's suggestion of sharing the gradients between rising and falling lines is a good technique. If you can get the gradient to 1 in 100 there are relatively few problems - most 'level' layouts actually have a gradient of this order present.
QUOTE ..Does anyone know the precise height of a hornby A4, A3 or 8F..
The UK loading gauge permits a maximum height just over 13 feet, and all these designs were built to that height. So that's a fraction over 52mm if the model maker gets it right (and it is right on the current Hornby A4, A3 and 8F), allow a minimum of 60mm height clearance over rail top.
I neded to provide enough clearance between lower and upper levels to allow bracing of the upper board with point motors also below that board. 3 inches clearance is OK for an overbridge, for example, but when you've got to clear baseboard supports as well you really need 4 inches, a figure which includes the thickness of the board and underlay. With my tests showing 1 in 70 was the steepest allowable to support 8-coach trains, a rise of 4 inches at that rate equates to an incline of 280 inches, or nearly 23 ft. I had planned for the scenic sections to be on the level, and the gradient down and up only for the hidden storage yards. But 23 ft down, 8-10 ft for the yard and 23 ft back up would require a loft three times longer than I currently have.
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So I've split the difference - scenic goes up 2 inches at about 1 in 80 and storage yards down the same amount at 1 in 70. I only need the full 4 inches once the main scenic section starts so that helped. However most of the incline is on 36-inch radius (or 72-inch diameter) curves. That just seems to work without any noticeable slipping.
It's also important to make sure your gradient is even. Although I settled on 1 in 70 you need precise carpentry to keep the gradient constant. I'm not a carpenter and I can see that at one end the gradient steepens for 2-3ft - probably to 1 in 60 - and the locos definitely notice. Perhaps going to have to adjust that there.
Incidentally my newest loco is Hornby rebuilt Bulleid - 34008 Padstow - and that seems much better: it will go up the gradients with 8 Maunsells and 2 Pullmans (none with weights removed), whereas the unrebuilt Battle of Britain will do at most 8 without some very prototypical slipping. The original BB weighs 320 grammes but the rebuilt Padstow 370 grammes which must make all the difference.
So I've split the difference - scenic goes up 2 inches at about 1 in 80 and storage yards down the same amount at 1 in 70. I only need the full 4 inches once the main scenic section starts so that helped. However most of the incline is on 36-inch radius (or 72-inch diameter) curves. That just seems to work without any noticeable slipping.
It's also important to make sure your gradient is even. Although I settled on 1 in 70 you need precise carpentry to keep the gradient constant. I'm not a carpenter and I can see that at one end the gradient steepens for 2-3ft - probably to 1 in 60 - and the locos definitely notice. Perhaps going to have to adjust that there.
Incidentally my newest loco is Hornby rebuilt Bulleid - 34008 Padstow - and that seems much better: it will go up the gradients with 8 Maunsells and 2 Pullmans (none with weights removed), whereas the unrebuilt Battle of Britain will do at most 8 without some very prototypical slipping. The original BB weighs 320 grammes but the rebuilt Padstow 370 grammes which must make all the difference.
RFS,
Something to look out for with Hornby locos, that has been quite consistent in my experience. Hornby fit tender pick ups, very helpful in ensuring efficient current collection, but these are a source of drag. New out of the box, the tenders are usually fairly free running. Most will run away from rest on my 1 in 80 gradients. Once they have accumulated a few hours running though, the 'brakes' go on. This has varied from example to example, but on the worst affected has been enough to almost eliminate any train hauling capability. This runs against my normal experience, which is that most rolling stock frees up with running, and suggests that Hornby may not have the best materials combination for their wipers and wheel plating. Adjustment to the wipers for very low contact pressure relieves the braking effect, but also largely eliminates any contribution to pick up.
You might care to try your BoB without tender, and see if it does better. If so, adjusting the tender pick up wipers will help.
Something to look out for with Hornby locos, that has been quite consistent in my experience. Hornby fit tender pick ups, very helpful in ensuring efficient current collection, but these are a source of drag. New out of the box, the tenders are usually fairly free running. Most will run away from rest on my 1 in 80 gradients. Once they have accumulated a few hours running though, the 'brakes' go on. This has varied from example to example, but on the worst affected has been enough to almost eliminate any train hauling capability. This runs against my normal experience, which is that most rolling stock frees up with running, and suggests that Hornby may not have the best materials combination for their wipers and wheel plating. Adjustment to the wipers for very low contact pressure relieves the braking effect, but also largely eliminates any contribution to pick up.
You might care to try your BoB without tender, and see if it does better. If so, adjusting the tender pick up wipers will help.
Thanks everyone, the advice has been really helpful, unfortunately I don't have a rolling road and all the necessary equipment to undertake such a scientific test! I've done quite a bit of redesigning and I've gotten the gradient to 1:92 which by the sounds of it should be fine, however it does mean I'll be needing a pretty enormous amount of flexi track! A loop around the mainline (up and down) works out at about 3.6 scale miles! It also means I'll be spending upwards of £600 on flexitrack alone...fortunately this is to be a lifelong project and I'm 21! Also the inclined section is a long way off...but it's never too early to plan!
Unfortunately splitting the difference isn't really an option on my layout, the two sections that require inclines are the loops and holding sections at each end of the mainline (upline, downline, goods) and go underneath and above the layout. All the 18" curves are hidden from view. The idea is to automate the large mainline (a tailchaser with a station stop in the middle, the signalling and automatic braking will be the tricky part, I wish Lenz would just sponsor me!) and to manually operate the 2 small and simple branchlines; I much prefer just sitting back and watching the trains with a beer than operating complex goods yards.
Unfortunately splitting the difference isn't really an option on my layout, the two sections that require inclines are the loops and holding sections at each end of the mainline (upline, downline, goods) and go underneath and above the layout. All the 18" curves are hidden from view. The idea is to automate the large mainline (a tailchaser with a station stop in the middle, the signalling and automatic braking will be the tricky part, I wish Lenz would just sponsor me!) and to manually operate the 2 small and simple branchlines; I much prefer just sitting back and watching the trains with a beer than operating complex goods yards.
We share a couple of tastes there, watching trains go by, and supping a beer.
I am in the early stages of a project to build a layout for 'watching the trains go by', that will also allow point to point services to be run when I want to do some hands on operation. Although the extra track to make the gradients easier may seem expensive, you do need somewhere to park the trains when they are not moving through the viewing area. When I first started designing, the plan was for a conventional fan of pointwork each end of 16 through roads to make a large storage yard. But then the penny dropped: DCC systems come with considerable scope for automation , and with the track sectioned, trains can be stored sequentially on plain track. Concealed plain track, previously only used for moving trains from A to B, now doubles up as storage, and no points are required. It's a considerable cost saving, although expenditure is required for the control system, but then I had planned occupancy detection for the storage yard anyway. A much smaller set of through sidings allows ''overtaking' so the sequence may be varied, and these sidings will actually be scenic, with one end on view as a passenger terminus station throat, the other end as a goods marshalling yard.
I am in the early stages of a project to build a layout for 'watching the trains go by', that will also allow point to point services to be run when I want to do some hands on operation. Although the extra track to make the gradients easier may seem expensive, you do need somewhere to park the trains when they are not moving through the viewing area. When I first started designing, the plan was for a conventional fan of pointwork each end of 16 through roads to make a large storage yard. But then the penny dropped: DCC systems come with considerable scope for automation , and with the track sectioned, trains can be stored sequentially on plain track. Concealed plain track, previously only used for moving trains from A to B, now doubles up as storage, and no points are required. It's a considerable cost saving, although expenditure is required for the control system, but then I had planned occupancy detection for the storage yard anyway. A much smaller set of through sidings allows ''overtaking' so the sequence may be varied, and these sidings will actually be scenic, with one end on view as a passenger terminus station throat, the other end as a goods marshalling yard.
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QUOTE the signalling and automatic braking will be the tricky part, I wish Lenz would just sponsor me!
I suggest you do some tests on this before finally committing yourself. I have tried this with Zimo and Lenz decoders. Both work but when you switch on ABC in a Lenz Gold, you switch in extremely slow stopping under normal control as well. This can be a nightmare - you switch to speed step 0 (ie stop) from a lowish speed and turn away. Behind your back, your loco will continue for whatever stopping distance has been set for ABC.
The Zimo's were fine. The show stopper for me on this has turned out to be sound. ESU Loksound don't support ABC. Unless all locos have ABC there's not much point in it.
QUOTE But then the penny dropped: DCC systems come with considerable scope for automation
Brilliant! I must examine the possibilities myself.
David
I suggest you do some tests on this before finally committing yourself. I have tried this with Zimo and Lenz decoders. Both work but when you switch on ABC in a Lenz Gold, you switch in extremely slow stopping under normal control as well. This can be a nightmare - you switch to speed step 0 (ie stop) from a lowish speed and turn away. Behind your back, your loco will continue for whatever stopping distance has been set for ABC.
The Zimo's were fine. The show stopper for me on this has turned out to be sound. ESU Loksound don't support ABC. Unless all locos have ABC there's not much point in it.
QUOTE But then the penny dropped: DCC systems come with considerable scope for automation
Brilliant! I must examine the possibilities myself.
David
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