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The Train Thread 2
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David S Send message Joined: 4 Oct 99 Posts: 18352 Credit: 27,761,924 RAC: 12 |
NS 1065 hits truck. Savannah and Atlanta will need a bit of cosmetic work. Trucker will need a new truck. David Sitting on my butt while others boldly go, Waiting for a message from a small furry creature from Alpha Centauri. |
Sirius B Send message Joined: 26 Dec 00 Posts: 24879 Credit: 3,081,182 RAC: 7 |
Don't forget that Fiat bought the patents for the APT tilting technology & incorporated it into their Pendolino design. The laughing stock that changed the world |
rob smith Send message Joined: 7 Mar 03 Posts: 22204 Credit: 416,307,556 RAC: 380 |
As Richard says "tilt" is about improving passenger comfort. In the early days of tilt it was assumed that one had to compensate fully for the lateral acceleration while going round a bend. This led to the reports of nausea (and sometimes "follow through") during the early trials of the APT. By reducing the compensation it was found that passenger comfort was improved and nausea was reduced. "Elevation" is to do with the steering of a train round a curve. This is all to do with the interaction between the shape of the wheel and the shape of the rail. The part of the wheel that runs on the rail is a truncated cone with the narrow end towards the centre line of the train. The top of the rail is set at an angle, sloping down towards the centre of the track. If the track were flat (no elevation) in a curve the train would take the curve in a series of straight sections, but titling the track the train effectively "falls" smoothly round a curve. (The maths is quite hairy, and I don't have the papers at home.) Bob Smith Member of Seti PIPPS (Pluto is a Planet Protest Society) Somewhere in the (un)known Universe? |
Richard Haselgrove Send message Joined: 4 Jul 99 Posts: 14650 Credit: 200,643,578 RAC: 874 |
The part of the wheel that runs on the rail is a truncated cone with the narrow end towards the centre line of the train. Are you sure? |
rob smith Send message Joined: 7 Mar 03 Posts: 22204 Credit: 416,307,556 RAC: 380 |
...no, I'm standing on my head :-( Thanks Richard, trying to type, eat, have a drink and the phone ringing is not conducive to the utmost accuracy. One thing to note from the picci that Richard has posted is that the flanges do not contact the rail most of the time. Bob Smith Member of Seti PIPPS (Pluto is a Planet Protest Society) Somewhere in the (un)known Universe? |
betreger Send message Joined: 29 Jun 99 Posts: 11361 Credit: 29,581,041 RAC: 66 |
One thing to note from the picci that Richard has posted is that the flanges do not contact the rail most of the time That is probably a good thing with less friction and less wear. |
Bill Walker Send message Joined: 4 Sep 99 Posts: 3868 Credit: 2,697,267 RAC: 0 |
The flanges may contact the rail when going around a corner, that's what produces the squealing noise you sometimes hear. In order to derail a car with a lateral load you need to lift the wheel enough that the flange rides over the rail. That requires a lot of energy. I'm told that a heavy car on a really tight curve will often grind to a stop before derailing. The main operational problem with curves is the extra drag produced, not derailing. As a previous post said, tight curves plus a slope can be especially painful. |
David S Send message Joined: 4 Oct 99 Posts: 18352 Credit: 27,761,924 RAC: 12 |
The flanges may contact the rail when going around a corner, that's what produces the squealing noise you sometimes hear. In order to derail a car with a lateral load you need to lift the wheel enough that the flange rides over the rail. That requires a lot of energy. I'm told that a heavy car on a really tight curve will often grind to a stop before derailing. The main operational problem with curves is the extra drag produced, not derailing. As a previous post said, tight curves plus a slope can be especially painful. Yes. In some places, the railroad will put a flange greaser on the rail to lubricate the inside of the rail head on the outer rail of a sharp curve. These have to be properly installed and well maintained so that the grease stays on the side and doesn't get on the top where it can reduce the locomotives' tractive effort. Someone once told me that squeal is actually the flange trying to climb up the side of the rail and falling down again. Also keep in mind that axles are solid and wheels are fixed to them, so on a curve one wheel is trying to go farther than the other in the same amount of time, but without going any faster. This results in one of them sliding a bit as it rolls. Again, less tractive effort for the loco, more friction for the cars. One more factor: all the wheels in a given truck (bogey) (or is it bogie?) are held parallel to each other, so there is even more forced friction between the flanges and rails. North American freight locos now being built have "radial" trucks, which allow the axles to turn slightly sideways to make curves easier. Radial trucks allowed Alaska Railroad to buy six-axle diesels for the first time, since they could handle the tight curves. Some of these factors have been designed out in certain high speed passenger equipment, but not all, and the solutions have to be very well-engineered or they cause their own bigger problems. Many railroads, once relieved of running passenger trains, removed superelevation from their curves because they didn't need it for freight only. David Sitting on my butt while others boldly go, Waiting for a message from a small furry creature from Alpha Centauri. |
David S Send message Joined: 4 Oct 99 Posts: 18352 Credit: 27,761,924 RAC: 12 |
NTSB report on a train crash in 2011. http://bustrainandtrolley.wrongfuldeathconsultants.com/index.php/ntsb-reports-tired-train-workers-caused-2011-iowa-crash/ David Sitting on my butt while others boldly go, Waiting for a message from a small furry creature from Alpha Centauri. |
David S Send message Joined: 4 Oct 99 Posts: 18352 Credit: 27,761,924 RAC: 12 |
Centrifugal force is mainly associated with high speed. I doubt this train was moving particularly fast, but if centrifugal force came into play, it would tend towards toppling the wagons off the outside of the curves. Thinking more about it, this is probably the best answer that was given. Centrifugal force is a factor, wanting to push trains off the outside of curves. Therefore, tight curves have speed restrictions on them. When a train loses its brakes going down a hill, it will usually stay on the track until it hits a curve and then fly off the outside. There was a story from the late 1970s about a rail train (delivering new rails in 1/4 mile lengths from the steel mill to where it was being installed) that ran away on Horseshoe Curve. This was in the bad early days of Conrail and too many of the cars had their brakes cut out, plus the engine's dynamics weren't working. The engineer kept calling out the locations they were passing, and the dispatcher kept giving him permission to pass STOP signals without stopping, like he really had any choice in the matter. The train finally stopped in downtown Altoona. They figured the low center of gravity and the continuous strength of the rails across many cars probably saved it from flying off on a curve. David Sitting on my butt while others boldly go, Waiting for a message from a small furry creature from Alpha Centauri. |
Bernie Vine Send message Joined: 26 May 99 Posts: 9954 Credit: 103,452,613 RAC: 328 |
Now for something completely different!! With the approaching festivities I decided to post a couple of train pics from the world of computer games. Now apart from trains my other hobby is RPG, or Role Playing Games, I am a fan of Bethesda Softworks and their games, notably The Elder Scrolls series and the Fallout series. The Fallout series takes place in a post apocalyptic future, that differed from our world in that after WW2 the transistor was never developed and the 50's visions of atomic powered cars and robots became a reality. The whole thing ended badly in 2077 with WW3. In various games you play a survivor from a vault who, 200 years after the apocalypse, sets out on various different missions across the hostile wastelands There was just one single subway car(with the same number placed countless times) in Fallout 3 however in Fallout New Vegas which takes place in and around the Mojave, my character stumbled upon a rail-road yard, and this: Not bad for a 200 year old loco :-) The latest offering in the series is Fallout 4, which takes place in "The Commonwealth" in and around Boston. I noticed that there were a lot more railway lines and rolling stock scattered about and eventually I came upon this!! It would appear to be a game designers idea of an "atomic" steam engine. Seems to be narrow gauge!! How do you get in the cab!!! Whereas the Fallout New Vegas E/F unit was the only loco I could find, in Fallout 4 I have so far come across 3 of these totally impractical monsters!! |
Jimbocous Send message Joined: 1 Apr 13 Posts: 1853 Credit: 268,616,081 RAC: 1,349 |
Now for something completely different!! Good grins. Thanks. |
David S Send message Joined: 4 Oct 99 Posts: 18352 Credit: 27,761,924 RAC: 12 |
Now for something completely different!! Looks like a decent F unit, but something's a bit off. The trucks, I think. That steam engine is pretty weird. David Sitting on my butt while others boldly go, Waiting for a message from a small furry creature from Alpha Centauri. |
zoom3+1=4 Send message Joined: 30 Nov 03 Posts: 65747 Credit: 55,293,173 RAC: 49 |
Now for something completely different!! And notice the F unit, says: Barstow Express Strong "Strong" doesn't make any sense to Me, but then I'm not a gamer. The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's |
David S Send message Joined: 4 Oct 99 Posts: 18352 Credit: 27,761,924 RAC: 12 |
And notice the F unit, says: Barstow Express Strong It's probably Barstow Strong Express. It's common for railroad heralds to have the last and/or most important word be the one across middle and most prominent. William Barstow Strong, president of the Santa Fe Railway 1881-89. Barstow, CA (and probably IL), Strong City, KS, and Stronghurst, IL are named for him. David Sitting on my butt while others boldly go, Waiting for a message from a small furry creature from Alpha Centauri. |
zoom3+1=4 Send message Joined: 30 Nov 03 Posts: 65747 Credit: 55,293,173 RAC: 49 |
And notice the F unit, says: Barstow Express Strong Ok, thanks David. The T1 Trust, PRR T1 Class 4-4-4-4 #5550, 1 of America's First HST's |
James Sotherden Send message Joined: 16 May 99 Posts: 10436 Credit: 110,373,059 RAC: 54 |
I actualy liked seeing how a steam engine could be imagined in the future. An atomic powerd one was one idea I had never thought of. really dont think steam power was developed 100%. The diesel engine killed it off before it was fully done. I wonder what some modern computer simulations and some realy savy design enginers could do with steam nowadays? [/quote] Old James |
David S Send message Joined: 4 Oct 99 Posts: 18352 Credit: 27,761,924 RAC: 12 |
I actualy liked seeing how a steam engine could be imagined in the future. There was a design in the 1980s for a modern steam locomotive called ACE 3000 that would be more economical to operate than a diesel, until the price of oil dropped. It was backed by Ross Rowland. Patent More interesting reading. Steam locomotive overview. David Sitting on my butt while others boldly go, Waiting for a message from a small furry creature from Alpha Centauri. |
Gary Charpentier Send message Joined: 25 Dec 00 Posts: 30651 Credit: 53,134,872 RAC: 32 |
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Bernie Vine Send message Joined: 26 May 99 Posts: 9954 Credit: 103,452,613 RAC: 328 |
Having done a little research since my pics. I of course discovered that my "atomic steam engine" would of course have been a "steam turbine" The PRR had a few From the http://prrsteam.pennsyrr.com/ page The S2 6200 a 6-8-6, built in 1944 largest ever steam turbine loco. Apparently turbines were most efficient at higher speeds. The emerging diesels put and end to development and 6200 was the only one of it class. Still looking at the picture, it is no so far a step to my "atomic loco". In the "Fallout" game universe, efficiency was never really looked at, it was all "bigger and better". Which was what lead to shortages of everything and eventually to WW3 that sets the whole story. In the game I have found another "trainyard" this has an owner NH&M As the story is set in Boston I assumed the New Hampshire and Massachusetts, although New Hampshire and Maine was suggested on another website. I also discovered a water tower. And a small switch tower (of which there are in fact several across the map). And finally another "steam turbine" I couldn't originally work out how it was propelled. Now I see that the turbine drove the large "cog" between the front two wheels, which is connected to the drivers. So upon reflection it seems the game designers did in fact do little research and in their alternative world, steam turbines could have become a reality. PS, when I did a picture search for "Fallout 4 steam locomotive", my own pictures from here came up 3rd and 5th!! |
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