Fifteen entries!
Great work everyone, but if you're going to try and break the forums you'll have to try a little harder next time
Because we have so many entries, I've decided to try something a little different. Instead of selecting just one screenshot, you can select the three you like best! This will ensure more votes are spread out among all the entries, and hopefully make a clear winner more apparent rather than have 30-odd votes stretched out among 15 screenshots.
Entries are closed, voting is open, get to the polls!
BW89
OK. I try it late too

Emperor Jake
The abandoned Tredegar Viaduct is a victim of the Beeching Axe. Clearly seen from the active station on the mainline, it is a popular destination for railfans and history buffs. The viaduct formerly carried a branchline which connects to a nearby town, but was closed due to another nearby line which follows a similar route but connects a larger town.
flogeza
Székely Gyors somewhere in Erdély (Transylvania).
ISA
Okay, some from me.
kamnet
The Wallace Viaduct carries traffic over a very busy rail line.
leifbk
<no caption>
luxtram
Transrapid vs. Porsche
It is subtle but it is a viaduct.
Pilot
Here we see Deutsche Cargo Bahn Train 31 (hauled by Voith Maxima 500 011) powering out of a tunnel onto the Schwabach Viaduct, about to run down the infamous Schwabach Spiral. The 1860s built Stone Viaduct groans under the weight of these behemoth Oil Trains, which weigh in at roughly 2,500 tonnes, a weight that was never envisioned during the Viaduct's construction.
piratescooby
My entry for this month the bridges of Hellholt.
Pyoro
I love how everyone has the exact some bridge-type in their screenshot, with different colours depending on the roadtype. So of course the Japanese-colored one can't be missing (totally the only reason I'm entering)!
Quast65
Not much time to make new screenshots, so an oldy but goody

SilverSurferZzZ
One way road to the world.
STD
Unique spiral viaduct railway is located near the town of Brusio in Switzerland.
The stone viaduct was opened on 1 July 1908, when it was commissioned the section of the railway Tirano-Poschiavo Bernina Railway. In 1943 the company was bought by the Rhaetian railway, which still operates the viaduct. This part of the Rhaetian railway is a world heritage site by UNESCO.
The radius of the spiral viaduct is 70 meters with a length of 110 meters. The slope is 7%. The viaduct is made of stone and consists of 9 arches each with a length of 10 meters. Train going down the mountain, passing through the top of the viaduct, and then passing under it, making a complete circle.
SwissFan91
The Ouse Valley Viaduct, built in 1841, is a Grade II listed 'building' located on the Brighton Main Line. Here we see a Gatwick Express returning from Brighton, passing a London Victoria - Brighton semi-fast Southern service on the viaduct.
trainman1432
A small farm rail yard and station are in the shadow of a large viaduct bridge on Hallamast Island.
A majestic Alleghany is pulling a 1 kilometer consist, delivering it to the nearby classification yard to be
shunted to other engines.
