I've tried before, but always failed. The Super Rail Cargo is an express EMU freight service that runs in the middle of the night and is a hard one to photograph. Turns out though, that Japan doesn't do daylight-savings. Therefore, in summer, in the wee hours of the morning, one has a good chance of seeing this thing on the move.
One service leaves Tokyo whilst the other leaves Osaka, around the same time, nearly every night of the week. I've never tried to hunt down the Tokyo end, as it's sorta out-of-the-way down past Shinagawa. Fortunately, the Osaka side passes through Umeda, on it's way towards (and along) the Tokaido Main Line.
The Stake Out - Fukushima Station
This train runs from Ajikawaguchi yards, along the Yumesaki Line, joins the Loop Line at Nishikujo, passes Noda and then heads north where it branches off the loop at Fukushima. It's even at road-level and there's a level-crossing, so you get an advance notice of anything approaching.
I used my freight timetables as posted here to know when it might arrive. It was my last morning in Osaka, a Tuesday, and I wasn't going to miss it this time.
I was staying in Tennoji and awoke at 4am. There were no train services at that time, so I found a taxi and asked to go to Fukushima Station. The driver alerted that there was nothing to be gained in going there, but I actually stated that I hoped to take a photo and he chuckled and agreed that it was OK.
It was around 4:40am and indeed still dark.. but I was very happy to have the sun rising.. although on the wrong side for a good shot. There were lively characters coming out of Karaoke venues or bars, but also people making their way to work.
At 5:05am, the booms triggered and an EF66 with a short rake appeared. It seems this would be ▲59 making it's way from Suita. I think I still had my polariser on at this point, not really knowing the best way to shoot in low light. Hence the photos are quite dark.
A loop line service came through at 5:12am... meaning that I could've slept in a little later and taken it from Tennoji. There was no way I was going to risk that timing though.
Either way... The gates then activated again and the M250 came through!
Not the best photos... but for the first time I saw the actual service in flight; whilst I had a camera ready. Success!