Question: The railway that absorbed the North Lindsey Light railway  opened its London Extension in what year?

Context paragraphs:
Whitton railway station (Lincolnshire): Whitton railway station was a railway station, built by the North Lindsey Light Railway in Whitton, Lincolnshire.  It was the northern terminus of the line from Scunthorpe (Dawes Lane) railway station.  It opened in 1907 and closed for passengers in 1925 and goods in 1951.

Winterton and Thealby railway station: Winterton and Thealby railway station was a station built by the North Lindsey Light Railway in Winterton, Lincolnshire, on their line from Scunthorpe to Winteringham.  The station was opened on 3 September 1906 and closed to passengers in 1925.  The line closed entirely in 1964.

Normanby Park railway station: Normanby Park railway station was a goods station, built by the North Lindsey Light Railway, in Normanby, Lincolnshire, England.  Situated some 1 7/8 miles from Scunthorpe it opened on 1 August 1912, the increase in traffic on the line being due to the commissioning of new blast furnaces at the nearby works of John Lysaght & Company.

North Lindsey Light Railway: The North Lindsey Light Railway was a light railway in North Lincolnshire.  It was later absorbed by the Great Central Railway and later, on grouping, it passed to the London and North Eastern Railway.  The railway is now mostly closed.

Winteringham Haven railway station: Winteringham Haven railway station was a port facility on the south bank of the Humber Estuary, Lincolnshire, England.  It was constructed by the North Lindsey Light Railway at the end of a 1/2 mile branch line from Winteringham.  The railway company provided two chutes to load ships, one for coal the other for slag, a by-product of the iron and steel making process.  It was opened on 15 July 1907.

Scunthorpe (Dawes Lane) railway station: Scunthorpe (Dawes Lane) railway station was a small railway station, the original southern terminus of the North Lindsey Light Railway situated adjacent to the level crossing on Dawes Lane and about 1/2 mile east of the present main line station, opened in 1926, and about 1/8 mile east of Frodingham railway station, Scunthorpes first station.

Winteringham railway station: Winteringham railway station was built by the North Lindsey Light Railway in Winteringham, Lincolnshire, England and opened for public service on 15 July 1907 although the first train, a village sports club special, had run two days previously.

Great Central Railway: The Great Central Railway (GCR) in England came into being when the Manchester, Sheffield and Lincolnshire Railway changed its name in 1897 in anticipation of the opening in 1899 of its London Extension (see Great Central Main Line).  On 1 January 1923, the company was grouped into the London and North Eastern Railway.

West Halton railway station: West Halton railway station was a station in West Halton, Lincolnshire.  The station was built by the North Lindsey Light Railway on its line from Scunthorpe (Dawes Lane) railway station to Whitton in north Lincolnshire.  The station was opened with the first section of the line (between Scunthorpe, where there was a junction with the Great Central Railway, and West Halton) on 3 September 1906; the line was extended from West Halton to Winteringham Haven on 15 July 1907.  Following this extension, the passenger service along the line consisted of three trains each way between Scunthorpe (Dawes Lane) and Winteringham , which called at Winterton and Thealby and West Halton.  The station closed on 13 July 1925.

Nidd Valley Light Railway: Nidd Valley Light Railway, was a light railway in upper Nidderdale in the West Riding of Yorkshire, England.  It was owned by Bradford Corporation Waterworks Department and the Corporation also operated its public passenger services.  Power & Traction Ltd of London obtained a Light Railway Order for the 6.5 mi railway from Pateley Bridge to Lofthouse in 1900, but these powers were taken over by Bradford Corporation.  A contract to build Angram Reservoir was awarded to John Best & Son in 1903, and he also won the contract to build the public railway and a 6.5 mi private extension to the reservoir site.  This was initially built to gauge but was converted to standard gauge by 1907, when the public railway opened.  Best had his own locomotives, and Bradford Corporation equipped the public railway with second hand locomotives and carriages from the Metropolitan Railway.

Supporting paragraphs: North Lindsey Light Railway Great Central Railway
Answer: 1899