For all the railway buffs and trainspotters out there: recently a very nice data set has been published with high resolution aerial imagery of the Dutch railway network. This data set is available as a WMS OGC Web Service via this URL.
The imagery has been flown in 2017/2018 on behalf of ProRail, the organization responsible for the maintenance of the public railway infrastructure in the Netherlands. The pictures have been taken from a helicopter (!!) from a height of only 190 meters on average.
To appreciate this imagery in your ArcGIS Online Map Viewer:
Go to Add > Add Layer from Web
Select A WMS OGC Web Service
Check Use as Basemap - this will allow you to zoom in to a level where you can spot individual railroad ties
Click GET LAYERS to check the layer 'meest_recent' (i.e. most recent) - this will show the imagery from 2017/2018. (The images taken in 2014, 2015 and 2016 do have a considerable lower resolution.)