True scale speed vs realistic looking speed

[Mac202]

After messing about with Complex speed curves I thought I’d have a go at determining what settings gave a true scale speed for my locos.

I set up a basic R3 oval that was 4.54 metre long.  Multiplying by 120 gave a scaled track length of 544.8 metres, which equals 0.338 miles.  Therefore 3 laps of the track is equivalent to 1.014 miles.

60 mph = one mile per minute, which means 20 seconds per lap of the track.  But setting the loco to run at this speed it just seems to be casually trundling along.  Nothing like the close to motorway traffic speeds I’d expect to see.

By adjusting the CV value for vHigh (and vMid) and timing the locos round 3 laps of the track I came up with what would appear to be the following true scale speeds for various vHigh settings, which seemed to be surprisingly slow.  So the question I have to ask myself is do a want my locos to run at a true scale speed around my track, which does seem to be rather slow, or do I want them to look like they are running at the type of speed I would expect.

I think I’ll revise my Complex speed curves for my locos to something that is a compromise between the two.

[ntpntpntp]

Personally I dislike seeing model trains flying round layouts especially on tight curves.  Trundling around calmly looks so much better and appropriate  in my opinion 🙂 If you have a large layout with long straights and sweeping curves then you can open up the throttle a bit and let trains swish by.

[Rallymatt]

I am not sure your scale speed calculation is correct. V High set to 195 on my OE motors in Gresley Pacifics gives a scale speed of 95-98 mph which is right for regular service, Google StonySmith Scale Speed calculator. All you need to do is determine the timing points you are going use, input the scale in the matrix and the distance between your timing points. Use the stop watch to record the time taken and hit Calculate for the scale speed. I find using this useful because you can just repeat tests until you match the speeds to a known throttle setting without having to do the manual calculation each time. 
Scale speeds do look more pleasing to me and worth the little bit of effort. As Nick pointed out, take into account curves, pointwork, bridges, speed restrictions and the likely speed of particular trains at the time. 
Something people often forget is that a fast train looks fast when it passes close by, trackside/platform but from a distance, less so. We generally operate/view our trains at a distance. 

Edited Monday at 14:06 by Rallymatt
Typo

[Hobby11]

I'm with NTP, high speed is for kids train sets! The reason it looks slow when it's going at the correct speed is because its a model and you can't view it from the same position as in real life. When I get a kid telling me to make it go faster I just say its not allowed to!

[Skelton Junction]

I’m a big fan of trundlers too

[david_watts1]

Less likely to have derailments and other accidents at a lower speed too.

[Mac202]

17 hours ago, Rallymatt said:

I am not sure your scale speed calculation is correct. V High set to 195 on my OE motors in Gresley Pacifics gives a scale speed of 95-98 mph which is right for regular service, Google StonySmith Scale Speed calculator. All you need to do is determine the timing points you are going use, input the scale in the matrix and the distance between your timing points. Use the stop watch to record the time taken and hit Calculate for the scale speed. I find using this useful because you can just repeat tests until you match the speeds to a known throttle setting without having to do the manual calculation each time. 
 

I've been on the StonySmith Scale Speed calculator and double checked my results against it.  The apps results are slightly more than mine - 0.6 mpg at around 40 mph rising to 2 mph at around 100 mph.  The curves on my test track would account for the slight difference.

With vHigh set to 160 my A4 Pacific was calculated to be doing 137.5 mph (or 139.1 using the app).  And with vHigh = 200 it was 167.1 (169.6) mph.

I'm sure the length of my test track is correct as I've calculated it from Hornby's quoted track lengths / radii and by using Anyrail.

[Mac202]

15 hours ago, Hobby11 said:

I'm with NTP, high speed is for kids train sets! The reason it looks slow when it's going at the correct speed is because its a model and you can't view it from the same position as in real life. When I get a kid telling me to make it go faster I just say its not allowed to!

Perhaps when I get some buildings and scenery set up it will have something to swish past and will then provide a better impression of speed.

[Rallymatt]

@Mac202, something is out there, I have run a lot of speed calculations with a lot of locos, many not mine. CV05 set to 195 reliably gives a scale speed of 94-98mph on all the Gresley Pacifics I have set up, over 20 locos. Use a tape measure to establish the ‘measured distance’ and it’s more accurate over a longer distance and on a straight. 👍

[Mac202]

Well I'm certainly not going to argue with a man who has far more knowledge and experience in these matters than me.  I'll look at it all again but if all else fails then Rule 1 will apply 😀

[Rallymatt]

Just a thought on this, what is C29 set to? If it’s activating the complex speed curve function whatever is written to CV5 & CV6 (High and Mid) is ignored. 

Edited Tuesday at 11:44 by Rallymatt

[Mac202]

I turned off bit 4 in CV29 to disable the Complex speed curve.  Also reduced the value of vMid to keep it less than vHigh.

[Hobby11]

As an aside back in the late 60s my local club, Preston MRC, had a permanent layout 25ft by 15ft and the circuit worked out at roughly a scale mile which made working out speeds easy! It also discouraged speeding as well as you could follow it all the way round as the fiddle yard was off the circuit. I remember running a freightliner train of 18 wagons, brake coach and MTK class 50 with two Triang power bogies. Even that rain didn't dwarf it!

[Ilmson]

On 17/09/2024 at 01:36, david_watts1 said:

Less likely to have derailments and other accidents at a lower speed too.

This is just as true in reality.

As a ten-year-old child, I was once allowed to drive a real driving school tram 🤩. Of course, I had to drive over the point at full speed. The driving instructor and all the adults present were very frightened by the loud rumbling😅. The tram stayed on track, however. But I had to vacate the driver's seat 😭.

So yes, high speed is more fun for children than adults.