Many years ago I studied at Lancaster University. I was in hall, on site, in a westerly facing room, and had a direct line of sight to the WCML about 700m away. The window was single glazed and I could easily hear trains passing, especially at night. Since then I've become qualified in Acoustics, and have worked professionally in noise assessment of road and rail noise sources, this included investigating the WCML upgrade from Tamworth to Armitage (changing from two tracks to four tracks to increase line speeds). More recently I've been working in the Milton Keynes area (not in the field of acoustics) and stayed in several places not far from the WCML, in particular the large flat development right next to Wolverton station on the WCML.
One thing I can say right away is that noise is taken much more seriously than it was: in house design and construction, in vehicle design, road and railtrack design and construction and in council planning applications. The result of this attention is that, despite increasing speed of traffic, especially on rail main lines, the impact of noise has lessened. In the case of Wolverton my flat had a facade exposed to noise from the WCML about 20-30m away, however there were no windows in the facade so very little noise penetrated: I was only aware of some large freight trains and engineering trains at night. This fits with my measurements and caculations of traffic on the WCML. Generally the more modern the vehicle, the quieter it is: Pendolinos and the various EMUs are surprisingly quiet. It is the diesel hauled freight (most freight movements are at night) and (when I did the measurements), the relatively slow Caledonian sleepers, which then included Mark II carriages with block brakes, which were the noisiest traffic.
Looking at your prospective house in Lancaster: the use of a noise consultant by Persimmon Homes is to ensure that the new houses fulfill planning conditions. Hepworth Acoustics report shows that my perceptions and measurements are correct: the night time noise level from the railway is louder than the daytime level. There's also some surprises in the report: the measured background noise levels (the LA90s) are, in the main, higher than the daytime ones. In the case of this site this may be related to the arrival of a ship at Heysham harbour resulting in more HGVs passing along the A683, or possibly local traffic, or noise from the railway (even though the acoustics report does not mention it as a perceived noise source at the measurement site). The railway line here is elevated (the report says 5m), therefore the edge of the embankment is acting as a noise barrier, reducing the measured noise at the sound level meter (the main source of noise from rail traffic is the wheels on rail). If the microphone had been raised to a reasonable level (say the first floor bedroom window level, where there may well be line of sight to the rails) then the measured noise level may have been somewhat higher (indeed, they will be). No extra noise protection measures have been incorporated into the houses, apart from those identified by Hepworths as being at risk from road traffic, and the one house and one block of flats that they believe are affected adversely by rail noise.
My advice is that, if your wife has easily disturbed sleep, you should avoid this property, which has no special noise protection measures (unless it is the 'one') , even though it is only 25m from the WCML.
