Over on his YouTube channel GusGorman402 has uploaded a tutorial which shows how he monitors ATCS (Advanced Train Control System) signals from trains. ATCS signals are found in the USA, and is used for things like communications between trains, rail configuration data, train location data, speed enforcement, fuel monitoring, train diagnostics and general instructions and messages.
In the video he first shows how to determine the frequency of trains signals in your area by using the US FCC database. He then shows how to download and install the ATCSMonitor software which is used for decoding the signals, and then walks us through configuring the correct settings within the software. The train signal audio is piped from SDR# to ATCSMonitor via VBCable, and received with an RTL-SDR and simple whip antenna.
Later in the video he shows how to fully set up the software with train databases so that the actual spotted train names show up. He also shows how to set up the dispatcher display which visually shows the current train locations and track configurations.
GusGorman402 has uploaded the tutorial in two videos. The first shows the full tutorial, configuration and demo for trains in the BNSF fleet. The second video shows how to monitor the Union Pacific fleet which uses a different protocol, which requires a slightly different set up in ATCSMonitor.