The world's oldest operating narrow-gauge locomotive will be running in Derby on a temporary railway.

A 2ft gauge line is being installed on site at train manufacturer Alstom to allow Prince, an engine built in 1863, to haul passengers in two original carriages being shipped in from the Ffestiniog railway in Porthmadog.

Prince will be joined by Trangkil No. 4 on the demonstration line, the last narrow-gauge steam locomotive built in the UK for industrial use in 1971, now based at Statfold Barn railway near Tamworth.

The narrow-gauge exhibits are being brought in for three-day event The Greatest Gathering, which is part of Railway 200, a year-long celebration of the creation of the railways.

Organisers said it will be the "largest ever gathering of historic and modern rolling stock".

The narrow-gauge line, which was traditionally used in more challenging terrain than standard 4ft 8½in gauge tracks, will be installed by volunteers from Alstom, Ffestiniog and Statfold Barn.

A spokesperson for The Greatest Gathering said: "In Britain alone, there were more than a thousand narrow-gauge railways, serving everything from slate quarries to seaside resorts.

"These lines were often lifelines for the communities they served, and many have since become beloved heritage attractions."

After Prince has been hosted in Derby it will return to its original line in North Wales.

In addition to the narrow-gauge railway, organisers have announced a 15in minimum-gauge railway, inspired by Sir Arthur Heywood's experimental railway at Duffield Bank near Derby, will also feature.

It will feature Katie, the first locomotive built by Sir Arthur for the Eaton Hall Railway in 1896 and now owned by the Ravenglass and Eskdale Preservation Society, and Anne, built more than 100 years later by Exmoor Steam Railway.

The Greatest Gathering will take place at Alstom's Litchurch Lane site from Friday 1 August to Sunday 3 August, and will show more than 50 rolling stock exhibits.