I used a crappy (noisy) old Radio Shack stereo condenser microphone in "wide" mode mounted about 5 feet from the tracks.
Being an excursion train, the compressors and other noise from the passenger consist drowned out the locomotive after it passed. Also, I really wish the attendant on the rear had not blown that "tweet tweet" whistle as he passed, but such is life.
Unbelievable, I'm searching for this sound for more than 10 years. Beautiful! I used to live in the US and maybe it is strange but one of my best memories are of the sound of the diesel whistle of a freighttrain. This one with the dog barking is the max. thanks. Now I hope I will be able to download it and I will put it in my cellphone. regards Frank