Got a bit puzzled by the mention of scale speeds in some publications/forums, especially as some imply it's a complicated process.
Am I correct in thinking that these are arrived at by simply dividing a mile (5280 feet) by 148 (for N of course) and measuring the time a loco takes to cover a fixed distance e.g.
1 foot covered in 10 seconds or 6 feet in 1 minute = 10 MPH
5 feet covered in 10 seconds or 30 feet in 1 minute = 50 MPH
Or is there some other more complicated formula I should be using? ???
Thanks in advance.
Ray :NGaugersRule:
That's pretty much it yes, your calculations are spot on :thumbsup:
Paul
I use this, http://www.mcr5.org/NMRA/articals/speed.htm (http://www.mcr5.org/NMRA/articals/speed.htm) . I can't remember if I got it through this forum or another one (which I don't use anymore). Although it's for Railroads (US) there is a custom box to add your own scale.
I use this:- http://www.nhsouth.com/crafts/workbench/ssc.htm (http://www.nhsouth.com/crafts/workbench/ssc.htm)
Can't really see the need for conversion sites as it's easy enough?
(mph) (ft/min)
10 5.95
20 11.89
30 17.84
40 23.78
50 29.73
60 35.68
70 41.62
80 47.57
90 53.51
100 59.46
110 65.41
120 71.35
125 74.32
Paul
I just turn the controller until it looks about right ! :bounce:
Quote from: trainsdownunder on January 23, 2013, 09:50:48 PM
I just turn the controller until it looks about right ! :bounce:
:laughabovepost: :laughabovepost:
That's me to a T :laugh:
My rule of thumb for BR Mk1s or earlier is: one coach per second is 40mph (50mph for Mk3s). Works for any scale (even 1:1), just count the seconds as the train goes by.
Hi all,
My annoyance with speed is not so much how fast the trains go (although some are ridiculously too fast) but the lack of slowing down to stop. More on youtube than exhibitions. I know some of it is remote control but it looks awful when a train is hurtling round, comes into the station and just stops.
Here endeth the little rant. Should be on angry thread.
I'm with the 'what looks right' guys as long as you all slow down gradually. Think of the passengers!
Cheers Weave
Some youtube videos show trains moving at TVG speeds when they're not
TGVs. I'll exempt the Addams family train wreck because it's so funny. ;D
Sprintex
Thanks for the speed table. I now have some backup to show my 4 year old granddaughter that she shouldn't really think Thomas shunts at 500 mph. :) Meeting Monday!
David N.
What is considered to be a 'good' slow speed (purely to test the loco's running qualities)?
I've managed to get around 3mph on DC from one of the Class 14's I had which seemed pretty slow. Does DCC improve this further?
Steve
Quote from: stevieboy on January 25, 2013, 01:26:13 PM
What is considered to be a 'good' slow speed (purely to test the loco's running qualities)?
I've managed to get around 3mph on DC from one of the Class 14's I had which seemed pretty slow. Does DCC improve this further?
Steve
I reckon 3mph is good enough for me. Anything less and terminal boredom would set in, methinks :sleep:
Mind you, it's great to have steamers at walking pace around shed areas :thumbsup:
Quote from: stevieboy on January 25, 2013, 01:26:13 PM
What is considered to be a 'good' slow speed (purely to test the loco's running qualities)?
I've managed to get around 3mph on DC from one of the Class 14's I had which seemed pretty slow. Does DCC improve this further?
It can do. With a CT decoder my class 24 really doesn't have a bottom speed. It gets to the point where the decoder will pulse the motor minute amounts at a regular rate and it crawls at about one sleeper a minute.
If you are getting down to a scale 3mph I'm not sure less is useful unless you are modelling an MGR coal setup or something similar !
I've been meaning to work this out for a while and due to seeing this topic just have, so :thankyousign:
This is what I found: a loop of my track (as measured on xtrakcad) is a little over 6m (6.06). Obviously this isn't exact and it depends on whether you take the outer or the inner loop (I've done an average).
This works out as a scale distance of 0.557 miles (6.06/1000*0.62137*148). I can then get the scale speed by dividing this distance by the time taken to do the loop (in hours (so time in sec/3600). Or if I pre-multiply the scale distance by 3600 I can just divide by the time in seconds - handily for me that number (0.557*3600) comes out to be roughly 2000 (easy to remember - 2005 to be exact).
The handy thing about measuring the time around the whole loop is that the times get big enough so the error in the timing is lower.
I hope that I've done that right - now my head hurts :help: but I'm going to try it out later.
Quote from: EtchedPixels on January 25, 2013, 03:19:15 PM
Quote from: stevieboy on January 25, 2013, 01:26:13 PM
What is considered to be a 'good' slow speed (purely to test the loco's running qualities)?
I've managed to get around 3mph on DC from one of the Class 14's I had which seemed pretty slow. Does DCC improve this further?
It can do. With a CT decoder my class 24 really doesn't have a bottom speed. It gets to the point where the decoder will pulse the motor minute amounts at a regular rate and it crawls at about one sleeper a minute.
If you are getting down to a scale 3mph I'm not sure less is useful unless you are modelling an MGR coal setup or something similar !
I think I just like having a benchmark for knowing how well the loco is run in and how well it's performing etc. They'll hardly ever run that slow when I'm 'playing'.
Just a thought: scale speeds are one thing; scale times are another. If your layout is to scale in terms of distance, you don't have a problem - but in most cases that means you are modelling a small section of a line. Here's the story for the rest of us:
If a real train travelling at a real speed of 60km/h gets from point A to point B in two real minutes, the real distance is 2km; that corresponds to a scale distance of 13.5 metres. On the model layout, the distance might be only one tenth of that, so the model system's "clock" must run ten times as fast. Then the model train, travelling at a scale speed of 60km/h (a real speed of about 0.4km/h), travels the 1.35 metres in 12 real seconds, but the model system's clock treats this real time as two minutes (120 seconds) of scale time. Stopping times at stations must also be adjusted, so that a reasonably realistic one-minute wait is reduced to a mere 6 seconds.
Unfortunately, the only supplier of clocks running at scale speeds that I ever found seems to have gone out of production.
- Michael
Scaling time can only ever be a compromise. The time between stations can be scaled but the time spent at stations, shunting etc can't be to anything like the same extent. To me a 6-second station stop would just look odd. If you want scale time I think the solution is to go by the scale clock for station departure times but to ignore it for all other activities.
Quote from: ToothFairy on January 27, 2013, 06:56:09 AMUnfortunately, the only supplier of clocks running at scale speeds that I ever found seems to have gone out of production.
JMRI can run a fast clock on your computer and send the time over LocoNet, if I understand it correctly.
I'm lost already :confused2: As Einstein would say it's all relative.
I've had 10 mins with a calculator and pencil and paper and
I can't get it right. A model running x meters in y seconds
is travelling at x/y meters per second , that is real time,
the same applies to a real train or plane, so I don't think
you can convert the model's real speed scalewise.
The answer is to control the model at a speed that looks realistic,
ie tank engines with a few wagons crawling along and HSTs etc
moving at 2-3 times as fast.
As edwin-m states some scale time would look odd (station example)
also points would switch so fast as to seem instantaneous.
This would make the use of slow acting point motors,
semaphores etc anomalous.
Let's assume your prototype (real or imagined) has two stations ten miles apart and a fastish train takes ten minutes from one to the other (60mph).
Ten scale miles in N gauge is about 110 metres and few layouts will have that much track between stations. But a largeish layout may have 11 metres or one scale mile. But then a train doing a scale 60mph would only take one minute to get from one station to the next.
You could therefore have a scale clock running ten times actual speed, so that going by this clock the train would take the correct 10min if it was running at a speed that looked realistic. It would also mean that trains would run more frequently (an hourly service would run every 6min on the model) which is probably a good thing. But as I said above, I think you would still make the station stop a real minute or so.
The important thing is that the speed does not scale. If you scaled the speed to take 10min between stations then the train would have to run at a scale 6mph instead, but that would not look very realistic.
Other options would be to have some hidden track between the stations where the train can stop and wait, re-write the timetable so that the train is scheduled to have less time, not bother with a clock and just have a "sequence counter" which is moved on when all the events due in a particular step have been finished.
After seeing all the algebraic and applied mathematics formulae regarding scale speeds I think my (and perhaps others) calculus method is the best.
"If I think it looks right to me - it's right! :) Always willing to learn new tricks though!
David
Quote from: edwin_m on January 27, 2013, 01:01:06 PM
Let's assume your prototype (real or imagined) has two stations ten miles apart and a fastish train takes ten minutes from one to the other (60mph).
Ten scale miles in N gauge is about 110 metres and few layouts will have that much track between stations. But a largeish layout may have 11 metres or one scale mile. But then a train doing a scale 60mph would only take one minute to get from one station to the next.
You could therefore have a scale clock running ten times actual speed, so that going by this clock the train would take the correct 10min if it was running at a speed that looked realistic. It would also mean that trains would run more frequently (an hourly service would run every 6min on the model) which is probably a good thing. But as I said above, I think you would still make the station stop a real minute or so.
The important thing is that the speed does not scale. If you scaled the speed to take 10min between stations then the train would have to run at a scale 6mph instead, but that would not look very realistic.
Other options would be to have some hidden track between the stations where the train can stop and wait, re-write the timetable so that the train is scheduled to have less time, not bother with a clock and just have a "sequence counter" which is moved on when all the events due in a particular step have been finished.
You seem to be missing the point . . .
ALL WE ARE DOING IS PLAYING WITH TOY TRAINS !! ::)
All this clock nonsense is complete overkill. Scale speed is just that: trying to make a train move at a roughly realistic speed rather than freight trains doing 120mph or Class 91 sets doing 160mph as mine will do if I turn it up to maximum. Let's not forget we have people that never go anywhere, cars that are mostly stationary in the middle of the road, and trains where the doors never open to let our glued-to-the-spot passengers on or off! Trying to get too clever with the time-space continuum is just taking the fun out of the hobby ;)
Paul
Messing about with the time-space continuum is not to be recommended, if you remember
the tv series Primeval. However from a model rail point of view it means you could justify
running Big 4 trains on a modern era layout by claiming they arrived via the anomaly,
also useful with the numerous changes in BR coach liveries post nationalisation..... :D
Quote from: Sprintex on January 27, 2013, 05:24:48 PM
ALL WE ARE DOING IS PLAYING WITH TOY TRAINS !!
Which is fine and good, but not a reason to shout down a discussion just because you don't want to take part in it.
Quote from: REGP on January 23, 2013, 09:19:21 PM
Got a bit puzzled by the mention of scale speeds in some publications/forums, especially as some imply it's a complicated process.
Am I correct in thinking that these are arrived at by simply dividing a mile (5280 feet) by 148 (for N of course) and measuring the time a loco takes to cover a fixed distance e.g.
1 foot covered in 10 seconds or 6 feet in 1 minute = 10 MPH
5 feet covered in 10 seconds or 30 feet in 1 minute = 50 MPH
Or is there some other more complicated formula I should be using? ???
Thanks in advance.
Ray :NGaugersRule:
Wow...by this measure with the controller all the way to the right my Dapol 0-6-0 Pannier can do 120mph!
Out of interest and assuming it is not pulling a load what would a 0-6-0 Pannier be capable of?
Quote from: lionwing on January 28, 2013, 11:34:54 AM
Out of interest and assuming it is not pulling a load what would a 0-6-0 Pannier be capable of?
Generally the real thing was limited to about 30mph. It depends on the wheel size. Some of the ones with larger wheels would top out about 45mph.
They were not fast beasties, but then most of the work they did was on branch lines that were rarely laid for fast running, or freight where fast running wasn't going to matter.
Steam locos are not generally geared so there is also a rather direct connection between acceleration, top speed and wheelsize that makes a tricky trade off. That's one reason DMUs could improve suburban services so much - even a first gen DMU had geared drive and far better acceleration.
Quote
Out of interest and assuming it is not pulling a load what would a 0-6-0 Pannier be capable of?
On occasion, 14xx 0-4-2s were clocked doing at least 70mph. Panniers have smaller driving wheels, so would be considerably slower.
9600 GWR 57xx Class 0-6-0 Pannier Tank - test run (http://www.youtube.com/watch?v=1fSdjZD9jnw#noexternalembed-ws)
might also be helpful - thats a larger pannier on test light engine.
Very good video, wee beastie fairly belting along. :thankyousign:
The video is great but clearly the Pannier doesn't look comfortable at such speeds.
I'ill be sticking with 30mph or so!
To get a feel of scale speed entering a station from a passengers point of view I fitted a wireless pinhole video camera to an old MK3 coach and it takes about a minute to travel the platform length of four foot, the last 6 inches reduced to a slow crawl up to the buffer stop. Its only when I look up from the monitor that I realise just how slow the model is running.
David
A minute to travel 4 feet is around 7mph so maybe a little slow?
Is it possible that one of our members into electronics could produce a CHEAP gadget to fit on our layouts to measure the speed of our trains or is there a CHEAP gadget on the market already ? I often see really good layouts at exhibitions spoilt by running at high speed and then as someone said almost stopping dead at a station then starting at a great rate back to rocket speed.
I'm not into electronics but I'm sure it's possible to make something and would be interested in buying something as long as it's not too expensive.
Bob
Why not replicate the Cecil J Allen method?
If your layout is long enough then add two mileposts a scale quarter-mile apart, which comes to almost exactly nine feet at 1:148. Time the front of the train from one to the other - a stopwatch would be most accurate but you can get an idea from an ordinary watch with a second hand, or even just by counting the seconds.
60s=15mph
30s=30mph
15s=60mph
10s=90mph
7.5s=120mph
That sounds a simple way to calculate the speed I agree ,But I would still like a visual indication to show you all the time as soon as your train is in the scenic part of the layout .bob
Of course you have all got it wrong ;-). It is not scale speed but scale acceleration that needs to be correct. The key, as has been mentioned is how the train enters or leaves the station. That is dominated by the rate of acceleration and not the scale speed that come later. What we nee is for some keen soul to do is take a videio of a train leving the platform and measure the time for the first carriage to pass a piont and then the next and ten the next etc. This can then be plotted on a log scale the angle of the gradient of the line is then the acceleration. Of cource the star A**** can use a spred sheet to fit a line through the points and define the acctual equation of the line. This can then bee used to calibrate the DCC inertia. (Ducks and runs for cover)
You're right, the acceleration has to be right too for stopping trains, not to mention the braking. As a further complication acceleration reduces at higher speeds and I don't think a DCC decoder can be programmed to do that.
If you can find the tractive effort of the loco used, and divide it by the weight of the train in the same units, this will give the maximum possible acceleration (as a fraction of the acceleration of gravity). This might be achieved once the train "finds its feet" but is still at low speed, so an appropriate acceleration leaving a platform might be say half to two third of this theoretical figure. You'll probably find it looks painfully slow, especially for steamers!
Braking for passenger trains will typically be about 5% of the acceleration of gravity, which doesn't vary much across the speed range. Modern trains are capable of 9% but use of maximum brake is discouraged.