Indian Railways , the world's second largest under a single management , has entered into a pact with Ffestiniog and Welsh Highland Railways , one of the world's smallest , to cooperate in a wide range of areas (link below.)
http://www.rmtbristol.org.uk/2007/10/indian_railways_in_twinning_pa.html#more

The Darjeeling Himalayan Railway , the first railroad to be granted World Heritage status , was modelled on Ffestiniog Railway and first opened in 1882. "The two railways will soon be discussing technology transfer of turning coal-fired engines into oil-fired," said Welsh Railway company manager Samantha Hughes at a Showcase Wales tourism event.

"The 'twinning' agreement will help in exchange of ideas on crossings, signal technology and even guard operations," Hughes said referring to the pact that allows exchange of ideas , knowledge and technology , among other issues.