Morning,
Just a question, as I am trying to learn to manage mainline speeds (45mph) and yard speeds (20mph).
In HO scale (1:87), if my engine travels 1 (actual) foot in 10 (actual) seconds, how fast am I traveling?
And can can you provide me the formula used or point me to a learning place?
Thanks
cplmckenzie
1 scale mile is approximately 60 feet in HO. If you travel 1 foot in 10 seconds you are traveling about 1/60th of a mile. There are 3600 seconds in 1 hour. Divide that by 10 seconds you get 360. Multiple that times 1/60th and you get 360/60ths which equals 6. You are going about 6mph. Since I started with an approximate figure, the final answer is an approximation as well but close enough for government work.
Modeling BNSF and Milwaukee Road in SW Wisconsin
Wow,
It seems like I am trying to go way to fast. As the longest stretch of straight mainline is roughly 4', much much shorter in the yard.
btw.
anyone know the mainline and yard speed limits?
Thanks again
cplmckenzie,
If you are wanting a more precise measurement of your sMPH, the following is what I posted recently in another thread. For conveniece, I created a quick-glance chart - for both switching speeds and mainline speeds - in Excel, printed it out, and hung it on the wall...
FYI: Calculating scale MPH (sMPH) isn't that complicated. All you need is:
Time how long it takes your locomotive to travel from Point A to Point B and calculate the following:
Example: It takes 15 secs for my locomotive to travel 3" (or 0.25')
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
jrbernierFor a rough estimate, do the following. 60 mph is 88'/sec. In HO, that is about 1 real foot(87 scale feet) but close). So, 10 seconds to travel 1 real foot should work out to 10 scale miles per hour. Myself, I would use something like a 6 foot timing section. That works out to 60 seconds to travel 6 real feet - still 6 scale mph. Jim
Jim, I think you made a typo when you wrote ten 10 miles per hour. You had the correct answer in your last sentence.
For anyone nerdy enough to want a more precise figure than 6mph, the actual number is 5.9386363.... mph. That's using 87.1 as the scale for HO.
jecorbett 1 scale mile is approximately 60 feet in HO. If you travel 1 foot in 10 seconds you are traveling about 1/60th of a mile. There are 3600 seconds in 1 hour. Divide that by 10 seconds you get 360. Multiple that times 1/60th and you get 360/60ths which equals 6. You are going about 6mph. Since I started with an approximate figure, the final answer is an approximation as well but close enough for government work.
In calculating speed, it's correct that you need to find a straight section of track vs, one curved? Also, I thought most moden trains go 40-55mph on the mainline (of course not accounting for weather, etc.).
Keep the below link in your smarphone or tablet.
http://home.cogeco.ca/~trains/rroperat.htm
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
tstageExample: It takes 15 secs for my locomotive to travel 3" (or 0.25') 0.25'/15 secs = 0.02 ft/sec Convert ft/sec to mi/hr and multiply by scale (or, 0.02 divided by 5,280' x 3,600 sec x 87.1) End result: 0.99 sMPH
I did calculations a while back and then went to a simpler system:
For HO inches travelled in 5 seconds equals smph. Your example gives the same result.
Dave
cplmckenzieIn HO scale (1:87), if my engine travels 1 (actual) foot in 10 (actual) seconds, how fast am I traveling?
6 mph (5 * 12 inch / 10 second)
1 mph in HO is ~0.2 inch/sec (5280/87/3600)
1 inch/sec is 5 smph (scale mph)
5 is the magic number
mph 5 10 15 20 25 30 35 40 45 50 55 60 in/sec 1 2 3 4 5 6 7 8 9 10 11 12
greg - Philadelphia & Reading / Reading
Some decoders will give you your scale speed if you press F10. That is if you are running DCC.
Google "scale speed calculator" and bring up western reserve. You can plug in any variables and get the scale speed