Fares vs. Distance

Did some work to check a previous statement (based on some now lost noodlings) that coach fares varied somewhat linearly with distance but sleeper fares varied in a step-wise fashion. Wrong! This graph of data for the Texas Eagle...



...shows (for this train) that Coach fares seem about as steppy as Bedrooms

Fascinating research. To those unfamiliar with your previous work (such as myself), would you explain the features of the graph?

Vertical axis is linear and is the fare cost for the portion of the distance to LAX (from CHI) the fare is for. The Coach (orange) plot is expanded vertically to sort of match the Roomette (green) plot so their non-linearities can be more easily compared. Bedroom fares were halved to match the curve heights of the other two. Each of the dots on the plot lines is one of the stations along the route of the Southwest Chief, but not all stations are represented by dots.

The vertical axes were not labeled because the purpose of the graph is to illustrate the nonlinearities in the fare structures - and not to find the fare to LAX from a particular station.

This graph cannot be used to find the fare from CHI to one of the intermediate points or the fare between any of the intermediate points.

Interesting to note that the Coach fare to LAX is the same along the 800 mile stretch from Pine Bluff AR to San Marcos TX which encompasses 18 stations. It's the flat part of the orange line below "Coach Saver Fares". That stretch is 29% of the total route! Bedrooms also have a lengthy flat spot.

Just made some changes to the graph in Post #1 to hopefully make it a bit easier to understand.

So it looks like the strategy, at least for the date of this graph, is to ride in coach to Bloomington-Normal and switch to a roomette from there to Los Angeles....

Doing that would save $189 or about 24% compared to going Roomette all the way from CHI to LAX. Just noticed I had the Roomette fares labeled as low bucket, but they're mid bucket and the graph has been amended. So picking a date when low bucket Roomettes were available would save even more - if you could find one.

Wonder what the plot for a Bedroom would look like. Hmm -m-m.

Couldn't stand not knowing for sure, so Bedroom fares were added to the graph.

OK, who'll be next with a similar graph for some other route?

niemi24s said:

Doing that would save $189 or about 24% compared to going Roomette all the way from CHI to LAX. Just noticed I had the Roomette fares labeled as low bucket, but they're mid bucket and the graph has been amended. So picking a date when low bucket Roomettes were available would save even more - if you could find one.

Wonder what the plot for a Bedroom would look like. Hmm -m-m

Click to expand...

Now, if you were technically ambitious, you could automate the query and plot the data for any given city pair (not just endpoints) for a particular date and make it web accessible, just like AmSnag.

[That would be a LOT of work. I'm not seriously suggesting that you take this challenge on. Still, if someone really was motivated....]

ehbowen said:

Now, if you were technically ambitious, you could automate the query and plot the data for any given city pair (not just endpoints) for a particular date and make it web accessible, just like AmSnag.

[That would be a LOT of work. I'm not seriously suggesting that you take this challenge on. Still, if someone really was motivated....]

Click to expand...

All that sort of thing is way, way above my head. My tools are an assortment of pens, pencils, scratch paper, graph paper and a hand held calculator - plus way too much spare time.

But even if someone were to do it, I'm not sure how useful it would be. Travelers customarily know where they are, where they want to go and AmSnag is perfectly fine for finding the cheapest fares between those two points. However, as with most things, there's probably a few things I haven't though of.

This mirrors analysis done by Matt' Johnson and I back in 2011.

Suggestions: Normalize your graphs for distance? They might be, but I can't tell given your X-axis goes from 0-1. Use a single Y-axis. You may be surprised at some of the things that come out, such as roomettes being more expensive than bedrooms for given segments.

http://discuss.amtraktrains.com/index.php?/topic/35761-a-look-at-fares-on-the-crescent/

http://discuss.amtraktrains.com/index.php?/topic/36205-amtrak-fare-comparisons/

Based on the 6 year old data, sleepers used to be the far "steppier" of the fares.

If by "normalized" you mean the x-axis is laid out in proportion to each stations' distance from the origin (CHI), then it's normalized. That's why the x-axis is labeled "Portion Of Total Distance From CHI to LAX". Just re-labeled the x-axis to "Distance To Los Angeles (Miles)" with mileages for every tenth of the route.

Because the purpose of the graph was to compare the linearities of the different fares (and not compare fare values from any particular point) the plots were expanded or contracted vertically so they'd occupy about the same vertical distance. Having a single y-axis would have given the plot of coach fares a total rise of only about 6 of the tiny squares on the graph paper - giving it the appearance of a fairly straight line. And a logarithmic vertical axis would have muddied things up, I think. AmSnag was used to find a period with about a week's worth of constant fares so the fares would all be from the same bucket.

Enjoyed your links to the previous work. Wish I knew how to do it that way. I have a hard enough time with my pen, paper and calculator!

Ryan said:

You may be surprised at some of the things that come out, such as roomettes being more expensive than bedrooms for given segments.

Click to expand...

Not surprising at all considering (except for 3 LD trains) low bucket Bedroom and Family Bedroom fares are less than high bucket Roomette fares, as seen below:



Even see it offered occasionally.

That's not what I'm talking about. If you were to read the linked threads, you would see low bucket compared to low bucket and the like.

OK, now I see what you were referring to, the second and third charts in the first link. Got curious to see if those peculiar cross-overs (for lack of a better term) still existed as shown between Roomette and Bedroom fares. Did a spot check of low bucket total fares at those major stations and found those crossovers seem to have vanished, as shown below by the broken lines added to those two graphs:



But I'm fairly sure peculiarities such as this originally reported still exist, if not on the Crescent route then some other route. Cripes, maybe all of them if one looks closely enough!

Dear Lord in heaven, Excel is your friend.

Ryan said:

Dear Lord in heaven, Excel is your friend.

Click to expand...

Sorry, never met the guy.

Finished updating the other two halves of the graphs of Crescent fares from 2011. 2017 Fares are shown by the broken lines below:



In addition to the disappearance of the crossovers between the Roomette and Bedroom fares (due to the wild excursions in Roomette fares), the large offset between the Northbound and Southbound fares out of Atlanta (top chart) are almost entirely gone.

Even though both graphs state the fares are all low bucket, these facts make me wonder:

• The jump in Roomette fare seen on the left side of the top graph is about $55 in 2011 dollars and a 1 bucket jump today is about $65

• The jump in Roomette fare seen on the right side of the lower graph is about $105 in 2011 dollars and a 2 bucket jump today is about $124

One of the disadvantages of graphing data in which one (low bucket Coach fares) is included in the others (Roomette and Bedroom total fares) is that it may not be readily apparent what is causing increases in the others. For those not accustomed to working with graphs it may not be too apparent, but for some parts of these routes the shapes of the Roomette and Bedroom curves (the broken lines) look just like the shape of Coach curve - they're the same vertical distance apart. This means that the only reason for changes in Roomette and Bedroom total fares is because the Coach fare increases - but the Roomette and Bedroom upcharges remain the same. For instance:

• On the left side of the upper graph the Roomette upcharge is the same $158 whether you go Northbound the 49 miles from ATL to GNS (the start of the lines on the graph) or the 634 miles from ATL all the way to WAS. The increase in the total Roomette fare is due solely to the $106 increase in the low bucket Coach fare. No change in sleeper upcharge over this distance which is 42% of the entire Crescent route.

• On the right side of the lower graph, both the Roomette and the Bedroom upcharges are the same $158 and $244, respectively, whether you go Southbound the 22 miles from CLT to GAS (the start of the lines) or the 776 miles from CLT all the way to NOL. The increase in the total low bucket Roomette and Bedroom fares is due solely to the $129 increase in the low bucket Coach fare. No change in sleeper upcharges over this distance which is 55% of the entire Crescent route.

These sorts of things may be more apparent when looking at tabular data. I'll post the tabular data if anyone <yawn> is interested.

Q: What other LD routes exhibit similar lengthy plateaus in sleeper upcharges?

Here's a graph of the fares from Atlanta with the Coach fare deleted from the total sleeper fares...



...which leaves just the upcharges for the sleepers. All are low bucket. This makes it much easier to see the plateaus.