I saw a couple of photos on RailPictures.net of a Loram rail grinder “reshaping the rails”. Are they resurfacing the top or flange side of the rails, or something else? I’ve never seen one of these before.
Tops. As wheels go around a curve one side is rolling and the other is sliding a little bit. That causes “corrugations” in the rail (little ripplesrunning across the top of the rail).
Dave H.
Kind of like having a “spool” in a differential. Got it.
How often do the wheels need to be replaced? I’ve heard cars go by at crossings that sounded like the wheels were very rough.
Thanks!
Wdgf,
What they are doing is grinding the rail back to profile, or crowning the rail.
The actual contact surface is very small, the top of the rail is round, and the wheel profile is slightly tapered, smaller dia on the outside face, larger on the inside face.
The contact area between rail and wheel is about the size of a quarter.
With a busy piece of track, the rail head gets flattened, on curves, the flanges dig a groove on the inside, and the rail head can spread and flatten.
All of that can lead to a wheel climbing the rail, real bad for business.
By reshaping the crown back into a ball, or round shape, the resistance is lessened, and the cars track better.
If you subscribe to Trains magazine, look at page 12, feb 2004.
The slice of rail on the left shows where the flanges have dug a groove in the inside of the rail, and note the the flattening of the crown to the outside.
On well maintained rail, the idea is to balance the cars on the rail, with the flanges not touching the inside of the rail, except in curves.
The sound you hear at a crossing most likley is a flat spot on a wheel, causes when the brake(air or hand) was left on, and the cars was dragged a long way thorugh a yard.
It may also be a build up of melted metal, or slag, formed when the friction of dragging the car heated the steel in the wheel, and the steel burned off the rail sticks to it.
Flat spots over two inches allow a wheel to be condemend.
Is the sound you hear confined to that one spot?
If so, it may be a small dip or groove in the rail, caused when a locomotive started pulling, and the wheels slipped.
If the engineer dosnt cut back on the throttle, the spinning wheel can wear a deep burn groove in the rail, a few inches long, which also makes the hammering sound as wheels pass over it.
Stay Frosty,
Ed
Once again, we may be talking cross purposes Doesn’t the wheel grind down before the track Grinds down… I know i have to keep yelling out “Don’t stop like that, you’ll CUBE the wheels!”
which goes first the wheel or the track?
In most cases the track goes first. Most rail that is installed is not ‘hardend’ rail as a consequence the wheels are normally a harder quality of steel and thus the rail burns first. I have seen rail where the wheel burn went completely through the ball of the rail. I think there is a former engineer somewhere that caused it. Rail burns, especially serious ones are a cause of hasty rail change outs. Hardened rail is used, normally on the ‘high’ rail in sharp curves to extend rail life and may be harder than wheels, I don’t know the relative Brinell hardness ratings for each.
Hi kevin,
BaltACD has your answer, the wheels are a harder steel.
I too, have seen where a rookie engineer, (piglet) burned through the ball of the rail.
Lucky for him, his conductor was walking back from the read end, and noticed. Had he managed to get it moving, the first car would have hit the ground hard.
Rails are made in a rolling mill, whereas wheels are poured, or cast, from a harder steel, then machined to size and shape.
Mudchicken will have the tech details.
Rail frogs are made with magnisum to make them even harder that the wheels, to prevent the wear rail is subject to.
Stay Frosty,
Ed
How many passes does it take to re-shape the rail? The Amtrak rail that Gunn is displaying, how bad/rare is that rail (shape).
I never thought of this. I always assumed the flanges were in more or less constant contact. This makes perfect sense, though, as that would wear the flanges out very quickly.
I think that describes what I’ve heard. It’s usually a car you can hear coming quite a ways away.
Tom- I’m no expert, but i witnessed a rail grinder on the CSX line heading west out of Baltimore last fall. I was down along the Patapsco river and the grinder only made a single pass. Sparks everywhere and a guy stationed on the back with a fire hose, putting out smoldering embers. He only made one pass that day. That line sees a fair amount of use. I know for certain at least one train a day (I usually catch it at 6:15 on my way to work). They may use it more than that., I don’t know.
(1) The number of passes is determined by the frequency of grinding, the budget (Grinders go for $7-10,000 an hour, screw the trains-let the grinder work!)and how bad the rail wear is…Have seen up to 12 passes on a piece of rail.
(2) Worn rail like what Gunn had (Borderline condemnable) is more common than you would think. BNSF just replaced 6 miles of curve rail on Raton pass like that. Looks like some roadmaster was unable to transpose it in time and all wore to one side. (Was that shiny new locomotive worth sacrificing rail life over Mr. Gunn’s predecessor???)
(3)Talbaneese: Think truck hunting!!!
Mudchicken[banghead]
Not sure what you mean? Sorry!
Hey Ed, the frogs are made of cast Manganese steel. Racor castings are explosion hardened (actually packed with explosives in a chamber and detonated) one of the properties of manganese is that when it is work hardened (when the parent metal is distorted when it is in its solid state, not molten) it becomes harder/tougher. As the surface of the casting getsbeat up it actually gets harder. It also has great wear resistance properties.
Talbanese, truck hunting is when the truck rotates slightly side to side letting the flanges contact the gage side of the rail. That’s one reason why most empties are restricted to a lesser speed than loads (with the exception of some cars that are equipped with constant contact side bearings ie. some articulated intermodals). Empties have a tendency to truck hunt worse.
Mudchicken, have you heard anything about the Nortrack buyout of Meridian Rail (ABC Naco)?
Ken
Truck Hunting: A lateral instability of a truck, generally occuring at high speed, and characterized by one or both wheel sets shifting from side to side with the wheel flanges striking the rail. The resulting motion of the car causes excessive wear in car and truck componets, and creates potentially unsafe operating conditions. - Railway Age Comprehensive Railroad Dictionary…
(1) All freight car trucks “hunt” a little bit (nothing restricts movement on the center pin)
(2) Each time the wheels stike the rail they take a tiny bite out of it…Powered wheels on a locomotive take a bigger bite. Thank god for steerable locomotive trucks…
(3) In curves, go too slow and you eat the low rail. Go too fast and you chew up the high rail. (What Gunn had was a rail off the high side of a curve…low rails tend to get “squashed” with metal rolling off in layers like an onion)
(4) What most folks see as hunting is at speed with unequal loading of the car accentuating the truck performance. Kinda like what happens when fire ants decide to crawl up the insides of your pants leg. Violent uncontrolled movement.
This being said, now think about what those trucks & wheels are doing to the rail! Now multiply that by every wheelset on every passing train.
Not said here yet, but rail grinding can easilly double the service life of the rail! If you are going to watch a grinder work, please do so from a Very safe distance. Broken high speed grinding stones can fly hundreds of feet in the air before landing.
Mud[banghead]
Ken: Had not heard about Nortrak and have been in Pueblo on a regulary basis the past few weeks. Will keep my ears to the ground on that one. Thanx!
Ken,
That explaines why our MOW welder had such a hard time welding a new point onto the frog at the north end of a crossover I use daily.
Took him a few hours.
Talbanese, imagine your car with the front end just a little out of alignment.
You keep having to correct your steering(hunt) to compensate for the balance.
Trucks will hunt for the balance mentioned, but due to very uneven loading, or worn bearings, worn wheels or less than well maintained track, they cant find it, they “hunt” back and forth from rail to rail.
Causes excessive wear to both the rail, and the wheel flange.
And no, the rail displayed in the magazine isnt rare, but it is badly worn.
Note only one side had the groove?
Who ever is in charge of that section of track should have had it swapped over,(transposed) long before it wore that bad, or reground at the least.
Stay Frosty,
Ed
Thanks everybody. When you say transposed I am assume that you mean switch the left track with the right track (High with Low).
If so, Do they cut the welded rail and then switch? How would that work.
Sorry for the stupid questions!
HI to Lo and Lo to HI is correct.
Generally the rail is cut just out in the tangent, just beyond the spirals. The spikes are raised just enough on one side to release the rail. On the other side, all the spikes are pulled and the rail is re-gaged after seating the rail in the tie plates. [ If one of the rails is really bad and there is no replacement in sight, rail in the tangent may get swapped for rails in the curve. This is partially why you sometimes see jointed rail in tangents and welded rail in curves.]The four cuts are barred (using regular angle bars) until the welders come along and do 4 boutet thermite welds. How quick and how well you do this separates the pro’s from the amateurs & wanna-be’s…Not a stupid question at all…
Mudchicken,
Thanks for the info.
I have seen the rail grinder and what it can do I have also tried stopping after he cleared up and we come thru. they lubracate everything . this is something you failed to mention that when grinding they lubracatre everything. something i forgot til i had to stop.