Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

HOW FAST AM I GOING, SEEMS FAST TO ME?! SEEM FAST TO YOU?

1390 views
12 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Thursday, August 1, 2024 5:35 AM

kasskaboose
Are you speed matching just locos?

what other than locos can you speed match?

 

kasskaboose
  It seems there are multiple other factors to consider.

of course, but isn't that what speed tables were intended to address?

greg - Philadelphia & Reading / Reading

  • Member since
    February 2008
  • 2,360 posts
Posted by kasskaboose on Tuesday, July 30, 2024 9:11 PM

Are you speed matching just locos?  I agree trying to compare two locos for speed is not really possible even with duplicate decoders and locos.  It seems there are multiple other factors to consider.

  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Tuesday, July 30, 2024 1:33 PM

maxman
One of those things could be whether the motor is cold or warm.

the speed track runs the loco for several laps (circular ~22" rad) to warms things up.    If a train is going to be run for any length of time, it makes no sense to calibrate when cold.

during a club open houses, a train may run contantly for 5 hours, i think in the low 20s smph.    when set properly, trains maintain they're distance from one another

greg - Philadelphia & Reading / Reading

  • Member since
    February 2008
  • 8,851 posts
Posted by maxman on Tuesday, July 30, 2024 11:32 AM

Getting back to the subject, I have done some speed matching and question any results that seem to imply a great deal of accuracy, or maybe I should say repeatability, from one test of a locomotive set to the next test of the same set.

The results can vary, probably due to many things.  One of those things could be whether the motor is cold or warm.  My "railroad" is basically a large loop.  I set speeds at 7, 14, 21, and 28 steps.   After recording the speeds I make the changes, and then operate the next loco.  In the interim the first loco motor has cooled and the values are not the same as originally set.  I can get close, but I don't believe that I can get a repeatable 1/2 smph every time.

  • Member since
    February 2008
  • 8,851 posts
Posted by maxman on Tuesday, July 30, 2024 11:17 AM

AEP528
Why did you pick a post that was no where near mine in the thread instead of the one immediately before mine?

If you had included a portion of the post to which you were responding in your post there would not have been a need for this portion of the discussion.

We are not mind readers.

  • Member since
    February 2008
  • 327 posts
Posted by AEP528 on Tuesday, July 30, 2024 11:13 AM

Overmod

Stix explicitly said ½-mph steps, so top speed of ~64smph.  That's actually slower than the speed allowed in many places for mainline  service (admittedly not in selectively-compressed "layout" mainline curvature)

To quote the OP who I was responding to:

For my field of play a throttle setting of 17 is, in fact, 17 smph! Likewise, 7=7. 23=23, 3=3, 28=28 etc., etc.,etc. All speeds in the range 1-35 are with in an average of negative 2% of the throttle setting. (i.e., a throttle setting of 17 results in a scale speed of 16.7 mph.) Close enough for railroadin.'

and

 Point is the NCE/Athearn Tsunami2 mix gives me the "one tap" 1 mph speed increase without any of the speed matching of which you speak

Why did you pick a post that was no where near mine in the thread instead of the one immediately before mine?

  • Member since
    September 2003
  • 21,669 posts
Posted by Overmod on Tuesday, July 30, 2024 10:45 AM

AEP528
So you have a max speed of either 14, 28,or 128 smph? If you're using 128 speed steps, you don't want to limit the max speed to something realistic?

Stix explicitly said ½-mph steps, so top speed of ~64smph.  That's actually slower than the speed allowed in many places for mainline  service (admittedly not in selectively-compressed "layout" mainline curvature)

  • Member since
    February 2008
  • 327 posts
Posted by AEP528 on Tuesday, July 30, 2024 8:55 AM

So you have a max speed of either 14, 28,or 128 smph? If you're using 128 speed steps, you don't want to limit the max speed to something realistic?

  • Member since
    July 2024
  • 9 posts
Posted by BillyJoeBob on Tuesday, July 30, 2024 12:32 AM

I simplifed the "speed matching" by using only Athearn.  From the Hi-Fi drive when I was a kid, to DC units, to now the Tsunami2 equiped units. At present, all nine of my Tsunami2 units run the same speed right out of the box. Point is the NCE/Athearn Tsunami2 mix gives me the "one tap" 1 mph speed increase without any of the speed matching of which you speak. Lucky for me F3, F7, F8, GP9 and GP50 engines all I need to play. The two Tsunami1 GP40-2 engines are assigned to yard duty with few excursions out on the main line - call them lower geared hump engines. Works for me. 

My speed trap is old school - six feet of track and a stop watch along with an equation that takes into account what scale the layout is. 

Simple is as simple does

  • Member since
    July 2024
  • 9 posts
Posted by BillyJoeBob on Monday, July 29, 2024 4:49 PM

What is the hand held reading for the 24mph speed trap result in the video. I don't care from speed traps - my scheme to to know the speed of an engine @ any time, any where a wheel is turning.

Athearn must have programmed the Tsunami2 to one mph per tap. I think that is right nice of them! Nice NCE!

NCE uses CVs 3&4 for consist momentum instead of CVs 23&24. My CV3 & CV4 values are 125 & 75 respectively. These values, when combined with a momentum rate setting of eight allows a set of road engines or a yard switcher, with a 2mph (tap tap) starting speed, to slowly to pull out any slack of a 25 car train or smaller yard cut and then just start at 2mph - slow enough to catch up. Most realistic; been there, done that.

A final note: these CV values are in all of the Tsunami2 decoders on the playing field. All of the engines so equipped and programmed as above run the same speeds. I have, from my first engine, an Athearn Union Pacific GP9 Hi-Fi drive, to today's DCC always owned nothing but Athearn units. Nary a problem, even in the good ol' Analog DC days.



  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Monday, July 29, 2024 11:22 AM

the club has both a speed trap to measure the speed of a loco/train, as well as a speed track for progamming the speed table to match the speed step on the controller.    not many locos can run along at a 100 smph

a member has run a few of locos on the speed track, but has also been running his numerous locos thru the speed trap just to compare speeds.    Many of the same model locos don't run at a close enough speed to be put in the same consist

greg - Philadelphia & Reading / Reading

  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 13,892 posts
Posted by wjstix on Monday, July 29, 2024 10:02 AM

Decoders as they come from the factory are not matched up with scale speeds. Different locomotives - even the same model from the same manufacturer - can have very different top speeds. 

With DCC, you can use CVs 2,5 and 6 to 'speed match' the engines so they run at the same speed at the same speed step, and use CV 3-4 to adjust the starting and stopping momentum so they all ramp up to speed, and coast to a stop, at the same rate.

I use an Accutrack II which tells you how fast an engine is going in scale MPHs (or KPHs if you wish). I use that for speed matching, setting all of my engines so each of the 128 speed steps equals 1/2 mph. 

https://www.youtube.com/watch?v=CWpWpma1b2Q

 

Stix
  • Member since
    July 2024
  • 9 posts
HOW FAST AM I GOING, SEEMS FAST TO ME?! SEEM FAST TO YOU?
Posted by BillyJoeBob on Sunday, July 28, 2024 6:24 PM

YEA, SLOW DOWN.

https://live.staticflickr.com/65535/53887975215_06be2aabd7_m.jpg

"I'll be catching up in two and a half cars." Bad track requires good speed control including how fast you are going when in a shove. This track is the main line entrance to Blueberry Yard.

 

After using DCC for a bit, I wanted to know just how fast engines were actually going. When the hand held shows 17, what was the actual scale speed the engine was moving?

With a NCE system and mostly Athearn Genesis w/Tsunami2 engines, what to do, what to do?

After much collection of speed trap data, tabelizing said data and much plugging and cranking in sophisticated mathematical expressions, the results are in. Caveat: all measurements were made after momentum effect stabilized.

For my field of play a throttle setting of 17 is, in fact, 17 smph! Likewise, 7=7. 23=23, 3=3, 28=28 etc., etc.,etc. All speeds in the range 1-35 are with in an average of negative 2% of the throttle setting. (i.e., a throttle setting of 17 results in a scale speed of 16.7 mph.) Close enough for railroadin.'

Tsunami1 equipped Genesis engines didn't fair as well. A throttle setting of 17 results in 12 mph.

This speed information is most useful when maintaining a prototypical 2-4 mph shove or playing trains with friends whom don't know from smph.

"This button makes it goes faster , see, tap tap tap, this one slows it down. Do not go faster than 20 and try not to hit anything."

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!