Getting off the commuter train the first day after my vacation - and digital noise

I recorded the last part of my travel to work, the first day after my vacation. Inside the train my recording equipment (Soundman Digital Recorder DR2) generates a lot of digital noise – more than usual. Interesting. Therefore I upload from when the commuter train stops at Gothenburg central station and the doors open and I walk away from the station.
The digital noise is there all the time but just less audible. In the beginning of the sound file you hear the noise clearly.

Don’t buy this little recorder… (It has a Sigmatel recording chip.)

In the frequency analysis, and spectral view, I notice peaks at about 800 - 950Hz, 7850 - 8350Hz and 16100-16450Hz. I guess this is part of the digital noise. Tried to EQ this away with spectral edit. This did not improve the sound. The noise has a wider spectrum.

Tried to download the “latest” firmware at www.soundman.de. Had to open command prompt and use unzip to extract the files. What?! But the Firmware downloader does not detect the “device”. I doubt there is a new firmware anyway. The year for this recording, according to the recorder, is 2002…

The recording starts about 07:50 Monday, August 07, 2017

I took 2 seconds from the beginning of this file and used paulstretch. Resulting in a 20second digital noise drone, “DR2 Digital Noise”,
https://freesound.org/people/gis_sweden/sounds/399075/
Had a thought that I could use a file like this to cancel out these frequencies from the other file with an inverted digital noise file… But I cant invert frequencies – off course :-D