p>Why did railroads display the elevation of their depots.
I can only guess on the “why” – and not all depots posted elevation – but railroads created track charts showing ruling grades and other changs in elevation, so their surveying teams were measuring this stuff anyway in order to plat out the rail line. Once the RR was built, those elevations often dictated how much tonnage could be put behind any given class of locomotive to prevent stalling out on the main, or to know where helper districts would be needed. It isn’t far fetched to imagine that the elevation was posted at the depot for the railroad’s own reasons and not necessarily for the public’s benefit.
That being said, elevation does influence many factors such as temperature of boiling water (which mattered to the railroads in steam days), existence of certain plants and animals (you sometimes read that ticks are never seen above a certain elevation), health issues due to extreme elevation, etc. What is clear is that it is important enough for most cities to post an official elevation on maps, with varying issues of where the elevation is measured from. This is true regardless of whether a railroad comes through town or not, and whether the elevation is high or low enough to be significant or interesting.
In any given town or village it was the railroad engineering department that was very likely the first to visit with the kind of tools that can measure elevation. I bet in some small towns their “official” elevation is measured from the depot just out of default.
Dave Nelson
Dave’s response above makes as much sense as anything I can think of. It seems to be an item of almost trivial data that nevertheless may have seemed important to the identity or character or nature of a town. But the elevation number says nothing about the steepness of the grade ahead or behind, or the elevation of the ultimate summit which is where the lowest pressure and temperature would be for boiling water to make steam, so it’s hard to see the usefulness to the railroad’s operating people of the elevation at a particular station.
But if the railroad did that, why not also/ instead post the Mile Post for the same station - such as ‘‘Julesburg - Elev. 623 A.S.L. - M.P. 129.6’’ [Note: These are made-up numbers; ‘A.S.L.’ = Above Sea Level; and the MP would be from the origin point of the line, likely the nearest big city, such as Denver, etc.]
- Paul North.
Elevation has NO effect on water in a locomotive boiler. It is a closed system under pressure. The pressure in the boiler would have a slight but insignificant effect of raising the boiling point but that is true of every pressurized vessel.
Bragging. To show how high the road is. Most often done by Western roads to impress Lowlanders and us Easterners. Elevation does effect breathing and excercise and for the neophyte visitor it is important information. Usually on the same board as distance to end points of either the railroad or the division. Informative to train crews who need to know. Even in the east some roads would so post as the idea was that mountain air was restorative in so many ways. If there is real serious side, it probably has to do with air pressure in train lines vs. outside. Boiling water, yes, in the diner but not in a closed boiler which creates its own pressure and internal atmosphere.
On that note, does anyone know of a watch or other simple device that can be used as an altimeter? There used to be a cheap LED watch that was available years ago but off the market and my jeweler cannot find another at any price level at this time. When riding trains or following old roadbeds I would find elevation an interesting fact of the moment.
True enough [tup] - but it would affect the ‘/_\ P’ or ‘delta pressure’, the change in pressure from high inside the boiler to the slightly lower pressure of the ambient conditions outside the cylinders and stack after the exhaust has occurred.
Not too sure about that - what’s ‘insignificant’, anyway ?’ - but I’ll let a mechanical engineering, thermodynamics, physics, or chemist-type answer that instead of me. In reading a late 1960s article in Trains on the D&H’s experimental high-pressure compound Consolidations, I remember being surprised by the tremendous increase in heat - in BTU’s contained in each pound of steam - as the pressure rose to the astoundingly high levels that those locomotives utilized. Where else would that energy have some from, other than more heat = higher temperatures, or maybe exposure to a constant temperature for a longer time or quantity of heat input, etc. But that’s my memory - which may well be faulty and I don’t have a good grasp of that technology anyway, so I’ll await a more detailed or informed response than mine.
I’ll go along with bragging - and just information for the passenger. I made up a “station sign” for the platform where we pick up kayakers - and included the elevation (1701’).
A point such as Big Moose on the NYC would be a fitting candidate, as it was the highest point on the Central system (2035’).
Henry6 - Most GPS’s have GPS and/or barometric elevation built in. They’re going for $200 and less now.
Paul, the Midwestern line I’m familiar with had mileages on its station signs. Although they were definitely related to mileposts, the sign on the building was probably for the public’s benefit as much as that of the employees. My hometown of Grand Haven, Michigan, had a sign with mileages on either side of the name (directionally appropriate, as the sign was on the track side of the building): “Detroit 188.30 Mi.” “Gd. Haven 0.00 Mi.”
Nothing about elevation on these signs. However, elevation–or probably the change in elevation–is not unimportant. The latest versions of UP’s employee timetables (those coming out since about the middle of this year) have a grade profile for each subdivision in them, along with the elevations.
Thanks, Carl. It’s good to know that at least 1 railroad shared my warped logic on such matters . . . [:-^]
The elevation thing - yep, I’d agree that it’s important, and it’s good that the ETT now has them - and the track charts as well, traditionally - but merely the elevation on the front of the non-portable station still seems to be essentially useless information in the wrong place to me, at least for the operating folks.
- Paul North.
The delta pressure change at 7500 feet is about 6-6.5 psi. Not enough to matter.
The increase in boiling point is insignifant precisely because it is the same in EVERY pressure vessel. Therefore comparing locomotives at different altitudes or locomtives to ships or power housesis moot. The increase in boiling point is the same for any given pressure.
As for BTU/lb of steam, that is more a function of superheating than pressure.
Yes…to the question of a watch w/ altimeter abilities. A year or so ago when I was looking for another {radio controlled}, watch I found a multi-purpose watch that took my eye, and it included an altimeter. I was on the verge of ordering it when I realized it contained so many functions but it did not include the {radio controlled}, function. I just looked now, and it is still available for $59 dollars.
It was a La Crosse brand. Simply go to a search engine and enter “watches with altimeter function”…There are several choices out there. I did choose a Casio brand {radio controlled}, watch, analog version and love it.
Edit: I used a La Crosse brand wrist watch {radio controlled}, for accuracy for 4 years and it did the job perfect…loved it too. Just wanted an analog {not digital}, and hence the Casio is what I use now.
I firmly believe that elevation displays at depots were only for the enlightenment of passengers, and for those who may be visiting the station. At the time passenger business was fiercely competitive RR’s provided lots of information to keep the passengers informed as they traveled.
These signs would have no significant meaning to operating employees and the engineering forces would have accurate data (bench marks or such) to use.
Thanks Modelcar…I will check it out.
Not much effect, but not NO effect. In the US, anyway (and probably everywhere else with the possible exception of Australia), “boiler pressure” as read on the gauge is the difference between inside and outside. So, lower pressure outside means lower pressure inside, for a given gauge reading.
Hmmm…it comes to mind, from waaay back, that there is such a thing as ‘vapour pressure’. In a pressure vessel at anything above ambient, or STP, you are reducing the vapour pressure as temps rise…? At some point you achieve a dynamic equilibrium responsive to inputs and outputs.
As for a gauge, is it a diaphragm type gauge, or a simple (in and out against a spring) gauge? I could see a diaphragm responding to changes on either side of it, in which case the gauge could read high or low relative to sea level, say. Were gauges’ graduations adjustable, slidable, to account for altitude?
But, if there is such a thing as a simple pressure valve actuator gauge, its cross section on the outside is unlikely to be affected, and it would respond to internal pressures only.
Just thinking…I am not very knowledgeable about these things, and it surely shows.
-Crandell
…On the subject of elevation signs at depots…years ago upon running automotive road tests from our area on out to Denver and up to Berthoud {sp?}, pass it was fun driving across the middle of America, which basically looked flat…but at each RR depot I’d see as we’d pass thru small towns…I’d note we were 25 or 50 some feet higher than the one back farther east we had passed thru, etc…All the way to Denver, when there was no question we were going up then…and so on.
But just why the elevation info signs were on the stations…I have no idea.
Some roads, such as the RG, UP, and SP, also showed, in their timetables, the elevation of each station. There may have been others, but these come to my mind at the monment.
Johnny
I’m sure “Diningcar” is correct. Operationally the railroad would not care what the geodetic elevation might be. A 2% grade was a 2% grade whether it was 900 feet above sea level or 9,000 feet ASL.
Without knowing exactly at what point that elevation was it was useless to surveyors. They would use a benchmark, typically brass embedded in a bridge abutment or bedrock, or sunk into the ground on a a long bar. Lists of benchmarks are available giving the elevation of each, and this very precise elevation occasionally gets revised as the continental level net is refined.
CNR in Canada put equally useless information on station nameboards on their transcontinental route, showing the distance to the end points of Montreal and Vancouver. Only the passengers (and want-to-bes) cared.
John
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Well said !
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That would be me/ us. Obviously by a knowledgable person - not many people are aware of the ‘dynamic’ nature of that data at that level of precision to keep it accurate.
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I bet that made the folks in Quebec and Halifax feel real good - about like chopped liver.
- Paul North.
…I wonder…Even from decades and decades back, railroads seemed to be sensitive to geometrically balanced designs…Designs that appeared nice…Think of passenger cars…even from way back to heavy weight design cars, how the whole structure seemed to be “balanced” in design…Proportions seemed correct…Roof designs were elegant…and stations / depots were treated the same way generally. Think of the gingerbread designs under the generous roof overhangs…the structures that may or may not have been structually in use to support the overhang, at least they were designed to look correct.
Possibly…they carried the design features beyond and railroading certainly was always close to engineering and detail, and who knows, perhaps the elevation boards as well as location signs were just part of the thinking of such designs. Something to be remembered by or for…A sense of importance. The {then}, center of the local activity.