It makes sense on the face of it, build an ore refinery next to the ore mine and just ship the processed metal out (hundreds of tonnes), rather than the thousands of tonnes of metal ore which will be largely 'waste' oxygen.

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Life on earth is the global equivalent of not storing things in the fridge.

No Water, in the days of steam engines the the train load was 50% water, just for the engine. It changed to diesel engines almost as soon as they were viable.

It makes sense on the face of it, build an ore refinery next to the ore mine and just ship the processed metal out (hundreds of tonnes), rather than the thousands of tonnes of metal ore which will be largely 'waste' oxygen.

Except that refineries last a lot longer than the ore supply does. Many refineries here in Canada have outlived more than one mine, because they have good rail or sea connections.

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It makes sense on the face of it, build an ore refinery next to the ore mine and just ship the processed metal out (hundreds of tonnes), rather than the thousands of tonnes of metal ore which will be largely 'waste' oxygen.

Not much good doing that if the mine is 1000km inland where there is no water where as shipping ports and refineries require lost of water. ;-)

Cheers.

1000km inland

Almost as far as Lake Ontario from the Gulf of St Lawrence.
Just kidding but here, there is a lot of water everywhere.

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...so the lead loco isn't expected to pull the whole 99k tonnes.

Guys. Basic high school physics. the 99k tons (or tonnes) is supported by hundreds of wheels under the hundreds of cars. All the loco sees is the weight of the train times mu (coefficient of friction), plus slope effects. The reason railroads are so efficient and so cheap is that mu can be very low, less than .01 if the steels wheels and steel rails are well maintained. That means the loco sees 1%, or less, of the train weight on level ground.

Slope effect is minimized by keeping the slope of the rails very low. For modern railroads a slope of 1 in 100 (one foot vertical change for 100 foot length of rail) is considered steep. For a line built specifically for heavy load hauling a slope of 1 in 200 is more likely the maximum. Using a small angle assumption, that means the slope effect adds no more than 0.5 % of the train weight to the load seen by the engines. (An earlier post quoted a slope of 1 in 250 in the loaded direction for one of the heavy lines we are talking about.)

Modern freight cars, even two at a time, can generate very high loads at the couplers under high acceleration or heavy braking. So, yes, every car can withstand the sorts of loads seen on long freights. You just have to keep acceleration and deceleration to small levels, easily done with modern electronic controllers.

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Actually positive accelerations are the ones that take the real control, as they are direct tensile pulls on the couplers, whereas negative accelerations are compressive. Additionally breaking is achieved on all vehicles in the train, not just the head-end loco(s). That said it is common to do a disproportionate amount of breaking using the dynamic brakes on the loco rather than the friction brakes.
Its fun to sit in an office in the UK monitoring the behaviour of a full SA ore train of three or four hundred loaded wagons, in real time (well as near as the satellites will allow) while it is descending to sea level. You see the train control system deciding to "trade in" another loco to relieve one that has been over breaking, meanwhile further back in the train a set of locos are actually applying power to get the tail round a curve and over a hump. All the while the driver is keeping the speed demand constant, and the traction controller is in top power notch!!! (and probably, more importantly, contemplating his next braai.)

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

Besides gravity, curvature is also a major source of resistance for trains. Think for a moment about the design of a basic truck (bogie to a good many of you (or is it bogey?)). There are two (three on most modern locos, and on older passenger cars to smooth out the ride) solid axles, each with a solid wheel fixed to it at each end. The truck is a rigid frame that holds the two axles, and thus the wheels, parallel to each other. So when it hits a curve, first, the outer wheel is unable to turn faster than the inner one and one of them has to slide a bit. Also, the wheels are unable to swivel to stay parallel to the rails. This introduces both resistance and a tendency for them to try to climb up the rail, which is the source of the screeching you hear when trains go around tight curves. In many places, railroads install automatic greasers along curves to lubricate the flanges without compromising the traction of the tread.

So, pusher locos help as much with overcoming this resistance, as well as the tendency to stringline the train, as with gravity.

Modern high speed passenger trains have independent wheels that mostly overcome these problems. American diesel builders in the last, I don't know, 20 years or so, have developed methods of allowing the axles to swivel a bit to at least relieve the rail climbing problem.

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

I think many modern freight bogies also have some limited axle swing, which helps as you said. Like the gravitational effects of slope, the power loss in a turn can be reduced by good track design. In this case, using large radius turns on modern rail beds. Power loss in the turn is also increased with speed increase. I watched a few unit trains loading coal in the BC interior and then unloading at Point Roberts on the coast. The loops at either end are the tightest radii on the run, and the trains are dead slow through these areas (for many reasons).

The total cost of transporting bulk goods is always a combination of capital costs and running costs. If you can amortize the capital cost of railroad construction and purchasing locos and rolling stock over many tons of freight, than very long trains on proper trackage remain one of the cheapest ways of transporting bulk cargo, as long as time is not a big factor. Second only to very large ships.

High speed passenger trains are a different calculation. If the distances are short (and therefore the capital cost of tracks relatively low) they can compete with airplanes given a good volume of paying passengers. Like in Europe or Japan. The same technology in the low population densities areas can only make sense if somebody else pays the capital costs, and if somebody subsidizes the running costs - like in China. Just my opinion, but it seems to be proven by the very limited number of profitable high speed trains in spread out, low population density, North America.

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trains loading coal in the BC interior and then unloading at Point Roberts on the coast.

Don't they have to chop off a few feet of rail every year at the docks?
I heard that it was due to the braking down hill on the tracks.....

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trains loading coal in the BC interior and then unloading at Point Roberts on the coast.

Don't they have to chop off a few feet of rail every year at the docks?
I heard that it was due to the braking down hill on the tracks.....]

Think I've heard that too, but I can't believe it true, as the switches near the docks would have moved and not work.

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Well don't quote me but, I heard that the CN Rail guys
have to add four feet of track in Halifax every year....

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Chris I think the little weighted carts are being used to straighten the track, after it is laid, although in North America we use powered machines for this.

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The little weighted carts are actually transporting material - the track is just sitting on crudely positioned sleepers. Once a reasonable section is in place a whole load more ballast is dumped and the tamping/aligning machine moves in. This packs the ballast around the sleepers while correctly aligning them. Normally this is done in two passes, the first a fairly crude run to get the general alignment set, then a fine adjustment and settling run. After the first pass the track is usable at low speed, but after the second it is good for speeds up to about 100mph. Being a new railway there will probably be a couple more passes before the track and track bed is fully stable.

The machine in Bill's picture is self powered, and basically pushes and pulls the track into place - you need much longer alignment arms to get into full alignment.

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

I think many modern freight bogies also have some limited axle swing

No, they really don't.

the very limited number of profitable high speed trains in spread out, low population density, North America.

Zero.

The closest thing we have to it right now is Amtrak's Northeast corridor, where Acela Express trains can go 135 MPH between New York and Washington (except in places with restrictions for one reason or another). This could be increased to 160 if they replace the overhead wire with a new constant-tension system. Acelas can also go up to 150 for a few miles between New Haven and Boston, but only 90 between New York and New Haven (Amtrak doesn't own the tracks there, therefore doesn't set the speed limit).

On Amtrak-owned track between Porter, IN, and Kalamazoo, MI, they can go 110. The state of Michigan bought another chunk of this line, extending east to Dearborn, and Amtrak is busy upgrading it to the same standard. Some trains are also allowed to go 110 for 15 miles of the route from Chicago to St. Louis. The track has been upgraded for 110 on most of this route, but the safety systems required by the FRA are not fully installed.

A private company is building a 110 MPH line from Miami to Orlando, eventually extending to Tampa, but it's facing NIMBY opposition.

The state of California has started construction on a true high speed line (200+ MPH) that will connect L.A. to San Francisco, with eventual extensions further north and south. Lots of political opposition there.

Other than that, the fastest any passenger trains go is 90, on segments of the Southwest Chief route in Kansas (except that the track has been allowed to deteriorate so that it's only good for 60 at best). This line still has a very old Automatic Train Stop system that legally allows that speed. Otherwise, the maximum is 79.

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

the little weighted carts are being used to straighten the track,

Which end has the rail cutters on it?

:):)

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trains loading coal in the BC interior and then unloading at Point Roberts on the coast.

Don't they have to chop off a few feet of rail every year at the docks?
I heard that it was due to the braking down hill on the tracks.....]

Think I've heard that too, but I can't believe it true, as the switches near the docks would have moved and not work.

I've never heard that, and I don't believe it.

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

I don't believe it

Awwwww David, would I try to have you on?

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I forgot to add, VIA Rail Canada trains currently go up to 100 MPH in some places. (Don't ask me where; I'm getting too sleepy to research it further.)

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

I don't believe it

Awwwww David, would I try to have you on?

You want me to answer that?

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David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.