Question: This 13.5 mi standard-gauge branch line railway ran to a civil parish situated about how far above sea level?

Context paragraphs:
Avonmouth Light Railway: The Avonmouth Light Railway (ALR) was a nominally independent railway company operating a short standard-gauge branch line from a point on what is now the Severn Beach Line near Avonmouth Docks station in Bristol to a Bristol Corporation electricity installation east of the main entrance to Avonmouth Docks.  Its promoters had aspirations which were never fulfilled.

Alston, Cumbria: Alston is a small town in Cumbria, England, within the civil parish of Alston Moor on the River South Tyne.  It shares the title of the 'highest market town in England', at about 1,000 ft above sea level, with Buxton, Derbyshire.  Despite being at such an altitude and in a remote location, the town is easily accessible via the many roads which link the town to Weardale valley, Teesdale, Hartside Pass (and towns in Cumbria such as Penrith) as well as the Tyne valley.  Historically part of Cumberland, Alston lies within the North Pennines, a designated Area of Outstanding Natural Beauty and is surrounded by beautiful views of the surrounding fells and the South Tyne Valley.  Much of the town centre is a designated Conservation Area which includes several listed buildings.

Alston line: The Alston line was a 13.5 mi standard-gauge branch line railway that operated in the counties of Northumberland and Cumberland in England.  Starting at its junction with the Newcastle and Carlisle Railway line at Haltwhistle, the line ran to the town of Alston.  An 1846 Parliamentary Act authorised a line as far as Nenthead, providing an outlet for the lead mines in the Alston area, and plans were made to connect with railways further south.  When the decision was made to terminate the branch at Alston, a further act was needed in 1849.

Aschaffenburg–Höchst (Odenwald) railway: The Aschaffenburg−Höchst (Odenwald) railway was a single-tracked, Bavarian branch line in southern Germany, running from Aschaffenburg to the Odenwald railway at Höchst im Odenwald.  Because the railway ran through the Bachgau, it was also known as the Bachgaubahn ("Bachgau railway").

Bylaugh: Bylaugh is a civil parish in the Breckland district of Norfolk, England 4.5 mi north-east of East Dereham and 13.5 mi WNW of Norwich.  According to the 2001 census it had a population of 65.  At the 2011 census the population remained less than 100 and was included in the civil parish of Sparham.

Skeyton: Skeyton is a small village and civil parish in the English county of Norfolk.  The village and parish of Skeyton had in the 2001 census a population of 200, increasing slightly to 207 at the 2011 census.  For the purposes of local government, the parish falls within the district of North Norfolk.  Skeyton lies 4 mi east of the market town of Aylsham, 13.5 mi south of Cromer, 13.4 mi north of Norwich and 129 mi north-east of London.  The nearest railway station is at North Walsham for the Bittern Line which runs between Sheringham, Cromer and Norwich.  The nearest airport is Norwich International Airport.

Carmarthen–Aberystwyth line: The Carmarthen–Aberystwyth line was originally a standard-gauge branch line of the Great Western Railway (GWR) in Wales, connecting Carmarthen and Aberystwyth.

Ruabon–Barmouth line: The Ruabon–Barmouth line was a standard-gauge branch line of the Great Western Railway across the north of Wales which connected Ruabon, in the east, with Barmouth on the west coast.

Kingsbridge branch line: Kingsbridge branch line was a single track branch line railway in Devon, England.  The line, which became known as the Primrose Line, opened in 1893 and despite local opposition closed in 1963.  It left the Exeter to Plymouth line at Brent and ran 12 mi , following the route of the River Avon to Kingsbridge.  A proposed extension to Salcombe was not constructed.

Bognor Regis branch line: The Bognor Regis branch line is a short branch railway line in West Sussex.  It is a branch of the West Coastway Line, a main line railway running between Brighton and Portsmouth.  The branch forms a trailing connection with the main line immediately West of the platforms at Barnham railway station and then proceeds in a broadly southwards direction for 3.5 miles to Bognor Regis, where all trains terminate.  All trains using the branch to or from Bognor Regis stop at Barnham.  The branch is operated with a shuttle train service from Barnham but this is supplemented with through trains to and from Littlehampton, Brighton and London Victoria.  The terminus of the line is Bognor Regis railway station.  All trains on the line are operated by Southern.  There is only one station on the branch, the terminus at Bognor Regis.

Supporting paragraphs: Alston line Alston, Cumbria
Answer: 1,000 ft