It is currently Tue Apr 23, 2024 9:26 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 8 posts ] 
Author Message
 Post subject: Static Friction vs. Kinetic Friction
PostPosted: Tue May 14, 2013 10:55 am 

Joined: Tue Sep 14, 2004 7:52 am
Posts: 2573
Location: Strasburg, PA
Saw this video and had to pass it along. It seems to show a lack of understanding that static friction between the drivers gripping the rail is always more that kinetic friction of drivers spinning on the rail. Holy crap, I’m glad that’s not my locomotive (or my track)! You can actually see dynamic augment in action at around 1:19.

Thanks to kwilcomb on the Narrow Gauge Discussion Forum for originally posting this.


Offline
 Profile  
 
 Post subject: Re: Static Friction vs. Kinetic Friction
PostPosted: Tue May 14, 2013 11:30 am 

Joined: Sun Aug 22, 2004 3:37 pm
Posts: 1276
Location: Pacific, MO
Don't they have sand on British locos? What is all the steam coming out around the drivers? I don't understand everything I see here. Other than very excessive slipping.
Maybe they should put aluminum oxide tires on her and do some rail grinding while they're out.


Offline
 Profile  
 
 Post subject: Re: Static Friction vs. Kinetic Friction
PostPosted: Tue May 14, 2013 11:36 am 

Joined: Tue Sep 14, 2004 7:52 am
Posts: 2573
Location: Strasburg, PA
I understand the British sanders run on steam, rather than air. I was thinking that the spot where she first let go was where she ran out of sand, but I don't know.


Offline
 Profile  
 
 Post subject: Re: Static Friction vs. Kinetic Friction
PostPosted: Tue May 14, 2013 12:13 pm 

Joined: Thu Aug 26, 2004 2:50 pm
Posts: 2815
Location: Northern Illinois
Is that engine superheated, with a dome throttle? It looks like he lost it with the units full of steam; finally decides at 1:25 to open the cylinder cocks and arrests the slip.

_________________
Dennis Storzek


Offline
 Profile  
 
 Post subject: Re: Static Friction vs. Kinetic Friction
PostPosted: Tue May 14, 2013 1:22 pm 

Joined: Fri Mar 26, 2010 11:43 am
Posts: 748
They were doing a burnout to get the tires hot for better grip. Just like at the drag strip.

Steam to deliver the sand seems like a bad idea. Always have a wet rail to keep things lubed up. Even worse if you run out of sand.


Offline
 Profile  
 
 Post subject: Re: Static Friction vs. Kinetic Friction
PostPosted: Tue May 14, 2013 1:29 pm 

Joined: Thu Nov 22, 2007 5:46 am
Posts: 2603
Location: S.F. Bay Area
The British invented wheelslip, and remain the masters of the craft, clearly.
Didn't they recently destroy an engine by overspeed during a wheelslip event?


Offline
 Profile  
 
 Post subject: Re: Static Friction vs. Kinetic Friction
PostPosted: Tue May 14, 2013 1:52 pm 

Joined: Fri Mar 26, 2010 11:43 am
Posts: 748
http://en.wikipedia.org/wiki/LNER_Peppercorn_Class_A2_60532_Blue_Peter
http://www.youtube.com/watch?v=YjsNbzg1UaI

That was nearly 20 years agao now, is that recent? That's 1/10th of the way or so back into the total history of the steam locomotive.

I think this latest video, they were just tired of continuously welded rail, and they are just putting the authentic clickety-clack back in the track.


Offline
 Profile  
 
 Post subject: Re: Static Friction vs. Kinetic Friction
PostPosted: Tue May 14, 2013 4:54 pm 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 6404
Location: southeastern USA
The more bits and pieces I pick up about tribology, the less I learn I know about it.....not always intuitively obvious.

British practice is a lot of oil lubing everything and steam wet-sanding......I'd imagine they would develop an early and extreme familiarity with wheel slip and how to control it.

dave

_________________
“God, the beautiful racket of it all: the sighing and hissing, the rattle and clack of the cars over the rails. These were the sounds that made America the greatest country on earth." Jonathan Evison


Offline
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 

All times are UTC - 5 hours [ DST ]


 Who is online

Users browsing this forum: Glenn Opande, Google [Bot], LVRR2095 and 176 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to: