Google maps are not great at showing railroad tracks.
These do show railroad tracks but so far don't have a Kursk offensive update
https://militaryland.net/news/frontl...ort-july-2024/
There is a set of railway maps of Europe and Russia here :
https://websites.umich.edu/~yopopov/rrt/railroadmaps/
The relevant one for the immediate Ukraine attack in the Koronevo area towards Kursk is 03-08
https://websites.umich.edu/~yopopov/...3-08_kursk.gif
This I think is the most relevant one for the area east of the initial attack, including the railway line from Kursk to Belgorod, 07-06
https://websites.umich.edu/~yopopov/...6_belgorod.gif
As far as I can see Ukraine is working to advance along axis that it can support using any railways it can connect to, and/or in order to cut any railways that are useful to the Russians.
In the first category the railway northwards from the Ukraine border through Koronevo and much further north Lgov / Sherekino. If they can reach Lgov they also cut the E38 east-west highway and threaten the Kursk NPP. Getting that far is rather unlikely but who knows. However it may well be an objective to take Koronevo, have a left flank on the river and a railway feed from Ukraine.
This suggests they are making progress towards the E38
Extending with other thrusts from further south and/or east may allow penetrations onto the 07-06 railway net that has two further border crossings onto the UKR railway net
(there are some twitter links in this - they aren't showing yet - I'll see if they come through in due course)