geolocating an image of a train

2023-09-17

word count: 930

approx reading time: 5 mins

this post is written in parallel with this one written by the awesome ryan, go check it out! ryan takes a different approach than i do here

this morning my friend maia posted a geolocation challenge, and i think it might be interesting to do a write up on how i solved it. this was a very approachable one, so i recommend you give it a go before you read the rest of this post! geolocation challenges are fun and always teach you a lot of interesting things

the prompt

this is the prompt maia sent, with no further context:

image of of a train at night. a house is visible in the background. the filename was PXL_20230917_012607611.jpg
image of of a train at night. a house is visible in the background. the filename was PXL_20230917_012607611.jpg

this is your last chance! stop reading now if you want to try it yourself.

gathering information

the first thing we do on a geolocation challenge is take a deep look through the image to pick out all the pieces of information that could be useful, without making assumptions.

  • the image is taken at night time.

  • there's a train, which has a series of red dots on the side, the number 2, and the text RBDe 56.... this doesn't immediately ring any bells for me, so i file it away as something to research later.

  • there is a house in the background, which has at least four floors, and a distinctive terrace which doesn't go all the way.

  • there are at least three train tracks. this doesn't directly imply we are on a train station, but there is a high chance we are on one.

  • one of the electric poles has a small plaque that reads [Z/2]61P. this also doesn't tell us much right now.

  • we can also check the original filename, which was PXL_20230917_012607611.jpg. pixel phones are Awesome, since they include a timestamp on the filename. this lets us know the image was taken at 1am UTC (or 3am swiss time).

the challenge was posted through discord, so the geocoding EXIF information was stripped from the image (but even if was there, we wouldn't use it, since that would defeat the point of this exercise).

as always, we run the image through google images, yandex, and other forms of image searching. in this case they fail to find any workable information, but they are usually one of the most invaluable tools when geolocating

research

now that we've collected a first pass of information, we can start doing research. searching for RBDe doesn't bring up much, but by searching for rbde 56 train we stumble upon the wikipedia page for SBB-CFF-FFS RBDe 560. SBB is the swiss federal railway, and since we know maia is swiss, we are probably on the right track here. this page lists a few variants, but none of them are the red-dotted train we're looking for. luckily for us, this page also talks about "Closely related trainsets", among which we can find the "RBDe 567":

this one does look like our dotted train! bingo! lets see if we can find more information about it, to see where these trains are used. with that, we should be able to get a (hopefully short) list of train stations our prompt could've been taken in. this trainset does have a wikipedia page, but unluckily for me, it's in german:

it does show various pictures, with which we can confirm this is the model we were looking at in the prompt. we can now use google translate to read the artic-

wait a second.

wait a damn second.

zoom in to that fifth picture.

enhance.

Enhance.

that house looks familiar. is that... is that the house? we have the quirky terrace, the handrail, three windows on the right side... it seems to match!

the image is captioned "trn ABt 204 und RBDe 567 316 im tpf-Anstrich mit tpf B 361 und 369 in Freiburg". i don't know what that means, but i know Freiburg is a city in switzerland. lets check the houses that surround the train station using google maps. it's always good to use the photogrametry data on google maps to get a quick look in, before we delve into the more time consuming street view.

that last house looks like the one we are looking for. thankfully, street view has some photosphere coverage from inside the train station, and even more luckily, it's taken at night time too:

verification

after finding a location that seems correct, we need to take some verification steps. this way, we can be confident it is indeed the same building, and not a standardized swiss house design. to do that, we look for details that are not specific to that one house.

the prompt and the photosphere were taken at different positions and with different angles, which makes this slightly harder, but we can see the plant on the terrace lines up, the poster on the door lines up.

post script

lets play spot the difference with the two trains in the previous picture. did you catch it? the train on the prompt has black painted windows, while the 567 doesn't. yep! it turns out we had the wrong train. in the process of writing these posts, ryan realized that the train on maia's picture is actually a rare color scheme on a 560. if you zoom into the text on the train, you can even see the top of that 0. it turns out, on 2021 the TPF sold it's 567 trains on the RER Freiburg line and replaced them with 560 trains, using this color scheme. that is why the photosphere and the wikipedia picture show the 567 (no black windows), they were both taken before 2021.

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