How long is the Equestria railroad ?

[SDP40F amtrak 2,447]

So I wonder how long is the Equestria railroad in Equestria

[Once In A Blue Moon 895]

By 'how long' do you mean the greatest distance between two connected points, or the total length of track laid?

If even a small town like Ponyville has a train station, then it's not unreasonable to assume that the rails run to every town and city in Equestria - if we work with that assumption then it would simply be a case of finding the two most distant towns.

 

If you want the total length of rail then that would require taking the surface area of Equestria and  multiplying it by the density of railway track length*. To do that, my thoughts would be that you would need to divide Equestria up into similar regions and then estimate the density for each of those regions - Canterlot, for example, as both a central city and the capital, would have quite a high density while the Everfree would have a density of 0.

 

An alternative take on it would require looking at how often railway lines need to be replaced. If you assume a certain rate of degradation then you can look at how much replacement track is laid down per year and use that to estimate the total length of track. Ideally you would divide Equestria into areas based on how fast the track degrades (heavy usage or damp conditions would mean that track requires replacing more often), but as the data would (most likely) already be divided into rail administrative areas you could make an estimate for each area.

 

The third option I can think of would require aerial (or satellite) photography of all of Equestria and computers to run machine learning programs that you would teach to identify railway tracks from the air. Given Equestria's (admittedly convoluted) technology level (if you were trying to solve this 'in-world') and the lack of detail on all provided maps (if you want to solve it with 'out-of-world' knowledge), that doesn't seem to be an option.

 

If you want a numerical value, I'd look at early-industrial records of rail length vs country size and estimate a density from that.

 

*the length of track per unit area.

Edited January 13, 2019 by Once In A Blue Moon

[FlareGun45 2,221]

The main cast keep having to sleep on train sometimes, so probably, at least 6 hours to get across country