NDA, my rear end.
Very well-established precedent in reciprocating aircraft motors is to use multiple-speed supercharging to maintain constant intake-tract pressure at altitude. A similar approach could easily be used on a locomotive since the actual peak boost pressure can be almost ridiculously small by comparison with 'high performance' supercharging (as e.g. with the diesel-sourced 6-71 Roots blower design used in drag racing, or on the turbocharging side the sequential twins used in truck or tractor pulling).
All you're assuring is that the engine performance at higher altitude matches specs at sea level.
In practice, it can be cheaper just to do as Kevin indicated and derate a 'standard' locomotive operating at a known range of altitude. But that's very different from saying that it's hard, let alone impossible, to do.
Steam locomotives, by contrast, lose comparatively little effective combustion heat release at up to 15K altitude but their cylinder efficiency can go up dramatically as you get into lower air pressure.
The giant railway layout, Miniatur Wunderland in Hamburg, Germany has a bridge between two buildings that connects Europe with the U.S, and South America. Anything is possible.
KBCpresident The thing would look like a frigging B-17 on rails, it'd be awesome! It'd require a lot of scratchbuilding, but still...
More realistic... push an armored gun car in front of the locomotive, and armor the locomotive.
The Polish, Germans, and Soviets did this in World War 2.
The gun car can be armor clad, or just a flat car with lots of sandbags. Both are realistic.
davidmurrayMany hotrodders put "blowers" on their engines. Would this work on diesels at high altitudes?
Basically, no.
The vast majority of diesel engines manufacturerd since 1984 have been turbocharged. Some stationary engines remained naturally aspirated for a while, but now nearly 100% of all diesel engines are turbocharged.
Installing a roots type blower (supercharger) on a diesel that is already turbocharged is pointless. A roots type blower is a positive displacement mechanical air pump. When the air coming in is thinner and below 14.7 PSIA it becomes less efficient.
A turbocharger, which is a centrigufal air pump, becomes faster as air to the inlet decreases, so it stays efficient at "lower" high altitudes, but there are problems if the altitude becomes too high.
Detroit Diesel manufactured some 53 and 92 series engines after 1984 that were both turbocharged and equipped with blowers. Their design needed the positive displacement blower to start and idle. Once under load, and the turbocharger built up pressure, the blower provided no performance benefit. This design was dropped in the early 1990s.
There were some bizarre experiments with different types of air pumps for diesel engines at high altitudes. These were mainly to address issues when heavy trucks operated in the American and Canadian Rocky Mountains back in the 1960s. One of these involved a mechanical "barrel type" supercharger driven by a second driveshaft from the transmission. I have seen drawings. It was crazy.
All electronically controlled diesel engines that I know of derate at high altitude, usually about 5,000 feet. There are "ambient air pressure" sensors installed on these engines so the control module can calculate operating altitude.
Mechanically controlled diesel engines also had provisions for high altitude derate of several designs. If these derates failed, the turbocharger would overspeed in the thin air and fail.
Beyond that... NDA!
-Kevin
Living the dream.
wjstixI recall watching a British-made TV series on trains around the world back in the 1980s where they visited a line in South America that (IIRC) crossed the Andes mountains. They noted that the railroad dieselized by buying diesels with the same horsepower as the steam engines, but then found they had to buy bigger locomotives (FM TrainMasters I think?) with greater horsepower, because the diesels didn't work as well in the thin mountain air.
Many hotroders put "blowers" on their engines. Would this work on diesels at high altitudes?
KBCpresidentDiesel engines are built and designed at lower elevations generally, and are air-breathing, so I'm guessing they could experience the mechanical equivilant of altitude sikness" at such high elevations a--slight decrease in efficiency.
I recall watching a British-made TV series on trains around the world back in the 1980s where they visited a line in South America that (IIRC) crossed the Andes mountains. They noted that the railroad dieselized by buying diesels with the same horsepower as the steam engines, but then found they had to buy bigger locomotives (FM TrainMasters I think?) with greater horsepower, because the diesels didn't work as well in the thin mountain air.
Given the fact that turbines had a relatively short life on real railroads, I'd have to assume there were no situations where they proved to be more efficient than either diesel or electric locomotives however.
KBCpresident think one of the appeals is the idea of having these massive turbine-powered locomotives slowly haul trains up the pass while soldiers in compartments in the short hood and the end of the long hood scope the landscape with machine guns. The thing would look like a frigging B-17 on rails, it'd be awesome! It'd require a lot of scratchbuilding, but still...
Far more likely an armored rider car(s) for the defending troops would be stuck ahead of and/or behind the power, although additional armour plate protection might also be added to the engine (and particularly the cab) to protect it and its crew from damage. But if you want protecting troops and firepower you want more space than just cramming them in the engine walkways. Give them a dedicated "fighting" car. You can also provide "defensive" cars at the front and rear, and maybe even spread throughout the middle at regular intervals depending on the train length.
Honestly your biggest problem here is going to be destruction of the physical infrastracture (track, catenary, power supplies) since the entire railway is in "enemy territory". The army might not be able to clear the whole mountain region, but you'll probably want a series of fortified facilities protecting the physical line, and allowing defense and repair teams to be dispatched to deal with bandit activity.
Chris van der Heide
My Algoma Central Railway Modeling Blog
I think one of the appeals is the idea of having these massive turbine-powered locomotives slowly haul trains up the pass while soldiers in compartments in the short hood and the end of the long hood scope the landscape with machine guns. The thing would look like a frigging B-17 on rails, it'd be awesome! It'd require a lot of scratchbuilding, but still...
If the bandits are camped out at higher elevations, do you think they would have soldiers and armored cabooses leave the major cities as well, or would they tack them on somewhere in route, maybe once they enter a more sparcely populated area.
You could argue that all the manpower would get expensive,but rememeber, there are royal subsidies to cover the cost of the firepower. The railroad only has to pay for the crew and private equipment
The Beaverton, Fanno Creek & Bull Mountain Railroad
"Ruby Line Service"
Thanks, everyone.
I agree the three phases of locomotives is a bit odd, that was just inspired by the Milwaukee Road. I could just put gas turbines on the point at a certian altitude.
No one has commented on the gas turbine idea. Does it make sense that Turbines would be ideal above, say, 10000 feet due to oxygen? I am just assuming that they would be based on a few assumptions:
Diesel engines are built and designed at lower elevations generally, and are air-breathing, so I'm guessing they could experience the mechanical equivilant of altitude sikness" at such high elevations a--slight decrease in efficiency. Whereas jet engines work better at higher altitudes, I'm assuming turbine locomotives would be more efficient up high.
Not on GN, not as helpers. On GN, a steam powered train would be pulled through the electrified tunnel area by an electric 'motor'. The steam engine would not be working, it was just along for the ride. Once enough diesels were around to displace steam, the electrics weren't needed anymore and the overhead wires were taken down. The diesel powered trains just ran through the tunnels on their own.
Initial reaction here was you shouldn't eat mushrooms while watching Lord of the Rings or playing Warcraft, but the more I thought about the idea I realized it wasn't far fetched. The place wouldn't need to be purely fictional as something like that would be at home in many parts of the world outside the developed urbanized nations. It used to be most model railroads were pure fantasy and no one tried for realism. Styles change over time. I think it would be cool to model a railroad in early 1900s Mexico or South America. Africa is another exotic modeling topic.
cv_acrWhy would you mix diesels (headend) and electrics (helpers) over the pass? Why wouldn't both the head end and helpers be the same type of power?
The Great Northern did it, due to ventiliation issues in the tunnels.
The Milwaukee Road did run hybrid consists on their Pacific extension, but I don't know if the electrics or the diesels served as helpers.
The rationale is unknown, but in the 1980 Conrail Conemaugh Division electrification study specially called for diesel helpers in electric territory. Gibbs & Hill did not offer any explanation for this.
KBCpresidentOk folks, this may be easily the most bizarre railroad story you have ever heard.
Not so much....a while back MR (or RMC or someone) had an article on someone building a layout set on the moon at a future date when the moon was being colonized and resources were being mined.
The late lamented "AWNUTS" magazine had some layouts that were pretty far out there too.
KBCpresidentPremise: The railroad would be set in a landmass consisting of a subtropical coastal seaport, and a Colorado-like plateau, seperated by a Himilayas-like mountain range. While the two kingdoms initally founght, they later merged into a single state, due to economic strategy. There are only two ways through the mountains: a severeral-hundred-mile detour, or a strait shot over what is accurately called "Bandit Pass". The latter is chosen to avoid the higher elevation, steeper grades, etc. of the alternative. The grades are still steep, trains run slow, and due to the rough terrain and hostile conditions the area is only lightly patrolled, making it ideal for train robberies. All freight trains are equipped with armed cabooses for this reason. In order to get military escorts on frieghts, the railroad is largely government owned.
EDIT: And I know a guy in my neighborhood who loves to mash and bash military models and weather them up nice. He would totally Mad Max your caboose for optimal defense in montane environs.
-Matt
Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.
Why limit yourself to EMDs??? Alco sold a large amount of locomotives internationally.
Santa Fe and Utah Railway got excellent performance out of the RSD-15 alligator on heavy trains and steep grades, and some Santa Fe crews preferred them over EMD's SD24's specifically for their lugging ability on Cajon Pass and due to their better dynamic brake performance than EMD SD24's on Cajon Pass (despite lack of typical EMD cab creature comforts). Utah Railway got good performance out of them on Soldier Summit, after Santa Fe let them go.
The Mexicans used six-axle Alco Centuries and MLW's to pull passenger trains on those steep grades in Mexico, sometimes triple-headed, during the time period you are referencing.
Alco/MLW diesels provided outstanding tractive effort at the lower speeds in heavy haul service (as long as you didn't run them through SP's 30 major tunnels on one line).
Otherwise, due to the number of long tunnels, everything else overheated for SP, so then you should be considering SD45T-2's and SD40T-2's during the era you are talking about. That is what and why SP preferred. Everything else (other than perhaps SD-9's) came up wanting in 4000 to 6000 foot tunnel lengths during that era.
SP's mainline over Tehachapi can be considered the toughest, most brutal operating conditions for any diesel model within the continental 48 due to all the grades and tunnels. The GE U33C and U36C's I guess did ok for SP, but did not hold up as well as the tunnel motors, and were present in lesser numbers.
Respectfully submitted--
John
Well, I know it has really happened that due to insurgents / revolutionaries etc. that there have been rail lines that had to have armed troops on the trains to protect them. Seems to me as recently as the 1970s Rhodesian Bush War the line from South Africa to Rhodesia (now Zimbabwe) was often shot at, and I think at least sometimes had armed troops onboard for protection.
KBCpresidentEquipment: Climbing out of both major cities, a fleet of EMDs would be used. Electric helpers would tack on to carry the train up the steepest grades, but due to concerns of winter icing on the catenary, the electrics cut off and are replaced by Gas Turbine locomotives
This is the part that looses me.
Why would you mix diesels (headend) and electrics (helpers) over the pass? Why wouldn't both the head end and helpers be the same type of power? If the line is electric, use electric engines. I'm not sure realistically why any railroad would electrify just the helper district and then only use the electrification half the year and maintain two sets of helper equipment. (Electrics and turbines.)
BEAUSABREYou want prototypes? Look up the Mexican Railway's climb from Veracruz to Mexico City via the infamous Maltrata Incline (over 4.5 percent in places)
Or just about any railroad that crossed over the rocky mountains to get to the Pacific coast.
Canadian Pacific's "Big Hill" (a "temporary" alignment to finish the railway that operated for 25 years) was about 4.5% grade until it was replaced by the Spiral Tunnels in 1909, basically a pair of real-world single turn helices tunneled into the mountains on either side of the valley and reduced the ruling grade to the desired 2.2%.
Other significant engineering projects such as the 5-mile long Connaught Tunnel (built 1916) or the 9-mile Mount MacDonald and 1-mile Mount Shaughnessy tunnels (built 1988) and other line diversions and realignments also lowered summits and grades on other parts of the route through the Rockies compared to the originally constructed route in the 1880s. Not too mention numerous other tunnels and bridgework on the original route.
KBCpresidentno unicorns
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
KBCpresidentThe setting is entirely fantasy, though realistic (no unicorns, giants, etc.). Equipment (where real equivilants exist) is based on North American railroading in the 70s and 80s.
That sounds an awful lot like Plausible Nonsense to me!
I am obliged to approve.
You mention the Tibet Railroad, and you premise sounds a lot like that RR, except the two kingdoms weren't exactly mutually merged.
This is all very interesting. I always pictured the pass bring heigher than 12k so I guess thats plausible too.
seems like my idea is only Farfetched when compared to some popular realistic operations philosophies. Tony Koester's project for instance. Based on his articles, he seems to take a very conservative view on realism. (Lest I be misunderstood though, I have nothing against the guy at all: I met Tony in Milwaukee about ten years back, and he was very polite.)
KBCpresident "Bandit Pass".
You want prototypes? Look up the Mexican Railway's climb from Veracruz to Mexico City via the infamous Maltrata Incline (over 4.5 percent in places) "From Orizaba the line runs parallel with the Rio Blanco, crossing three tributaries of the river, and winds its way up through the Infiernillo (“Little Hell”) Canyon to Maltrata (ninety-five and a half miles), achieving a height of 5,560 ft by tunnels and bridges. Beyond Maltrata the line twists and turns in all directions as it makes its way upwards. Looking back from the observation platform at the rear of the train, the passenger can see as many as six sets of track in the valley below.
From Alta Luz (ninety-nine miles), where the gradient in places is as steep as 1 in 22, the view of the plains is magnificent. The train passes over Wimmer Bridge, 90 ft long and built over a chasm, and gains Boca del Monte (“Mouth of the Mountain”), 108 miles, at an altitude of 7,924 ft. This station lies on the eastern edge of the great central plateau of Mexico. The stiffest part of the climb is now over, the line having ascended more than 5,000 ft in less than forty-two miles." Ferrocarril mexicano hi-res stock photography and images - Alamy Peru Central, for many years considered invulnerable to airlines, as no aircraft in Peru could operate at the altitude that it's Beyer-Peacock Consolidations could! "The Callao, Lima & Oroya Railway opened to Chicla by 1878 and reached La Oroya by 1893 and Huancayo (346 km or 215 mi) in 1908.[7] It is the second highest railway in the world (following opening of the Qingzang railway in Tibet), with the Galera summit tunnel under Mount Meiggs at 4,783 m (15,692 ft) and Galera station at 4,781 m (15,681 ft), requiring constructional feats including many switchbacks and around 60 each tunnels and steel bridges. In 1923 a branch was opened from Ticlio (making it the world's highest junction) to Morococha via La Cima (4,818 m or 15,807 ft above sea level), from where in April 1955 a spur line opened to Volcán Mine, reaching an (at the time) world record altitude of 4,830 m (15,850 ft). Both branch and spur have since closed to traffic"
If that's an unwritten rule, nobody told Kevin. His Stratton and Gillette is set in a totally fictional locale. The great thing about model railroading is we can make it as realistic or as fanciful as we choose. The railroad you describe would not be my cup of tea but if it's what you want, go for it. Your approach reminds me a little of Malcolm Furlow's. I don't know how many remember him. I think he once wrote, "Reality is a crutch".
My own freelanced railroad falls somewhere between realistic and fanciful. The modeled portion of my layout represents completely fictional towns but my staging yards represent real cities and it interchanges with real railroads. Some of those have trackage rights over a portion of my layout. My goal is not to model something that existed but something that could have existed.
Is a very long tunnel out of the question?
York1 John
I asked my doctor if I gave up delicious food and all alcohol, would I live longer? He said, "No, but it will seem longer."
One of the things I've been banging around, but never had the space (no puns intended) to do justice to, is the high-speed rail connection between Ecuadorian sea level and the high-level spaceport (and semiballistic hypersonic facility) firing east over Brazil.
All heavy equipment and likely propellant would be carried this way. It might be plausible to combine high-speed rack or Fell sections with automatic switchbacks to get the right mix of speed, capacity, and cost.
One note: the amount of electricity generation produced for some types of launch assist would make electrification a logical 'zero-carbon' choice...
(I've tried to post this twice but the stupid ad at the bottom of my phone has a blue link just like submit button keeps taking me off the webpage when I try to post )
I'm a bit surprised no one mentioned the literally outlandish setting. It seems to be an unwritten rule in MR that your layout should be set somewhere on Earth, or is that just because that's easier. I realize it's a hobby and there are few hard rules. It seems like after awhile you just have to ignore the advice you don't need/want regarding how to go about your pastimes.
mbinsewi Have a great Labor Day! Mike.
Have a great Labor Day!
Mike.
OvermodWe need to introduce him to Jared the Artist.
That is exactly what I first thought.
His idea was the craziest thing I had ever heard.
And to think, I thought my ideas were nuts.