Well, as I work down there, think ill add my answer here too...
Eastleigh isn’t that bad a place, good connections by rail to Winchester, Salisbury & Southampton...
But, where the postcode given is, is between DBS's North yard, and Twyford road - one of the main roads in and out of Eastleigh...
Also, there is the airport which, stating the obvious, gets nosier the nearer you are to it... again, the postcode given is almost under the Flight Path - when they take off in that direction...
As for the noise of the railway, well, you will get the obvious noise from the passing trains - but the 450s & 444s shouldn’t create too much noise...the main noise would really be from freights & the unsurprising XC Voyager - which when stabling overnight in the DBS Depot, are constantly left running on Idle throughout the night...so dependant on where abouts you are in Eastleigh, they do create a drone sound... - looking at the postcode given on Google maps though, I very much doubt you’ll here the stabling voyagers from that end of the town...
Passing Night time trains - shouldnt bother you at all, i rareley hear any freights at night, and SWT services! None at all
- last tain from London Waterloo is the 01:05, and is usally just a 4 car 450 anyway...so i certainly hear very little noise (in fact, i pretty much fail to hear them at all!)
Now, Onto the motorway - can't hear it... in Eastleigh, unless your near both motorways, you really dont hear them at all...
Sotton Airporty is quite a busy airport - no where as near busy as the likes of heathrow or stansted, but...it can have it's busy moments (plaines every 15 mins) but again, the sound depends on where abouts you are in the town...working by one of the yards you do obviously here them...And they can range from the Mid Sized Jet Engined, to the small single/double independantly owned / privitely owned plaines...
Advantages to Eastleigh - Youve got quite a good selection of open spaces around the town and you are vary close to the country...aswell as a good Rugby Club & sports ground on the opposite side of the yard - ie over the bridge y the railway station and past the newley opened Model Shop...
http://maps.google.co.uk/maps?q=so5...BR&redir_esc=&um=1&ie=UTF-8&sa=N&hl=en&tab=wl
What i suggest is that you go to the propertey, spend some time at the place ( ie a tbontb{To Buy Or Not To Buy} style test drive is best), check the road out at busy & less busy times...and really do your homework to see if the place is the right place for you...
So theres my bit anyway...Hope it's of any use to you...