Severn Lamb, the specialist UK transport engineering systems manufacturer, has announced the delivery of two new Texan rail trains to Louisville Zoo in the US.

The new trains are replacements for those previously in operation at the zoo and were ordered after an accident in 2009 when one of the old trains was derailed.

Historically, an open-air train ride has been a central part of the zoo experience, but no such rides have been available since the accident.

Severn Lamb subsequently won the tender to design and build two new trains for Louisville Zoo to begin operation in the summer of this year and it's now 'full steam ahead'.

The two Texan trains operate on a 24-inch gauge track and are made up of 4-4-0 locomotives and eight-wheel diesel hydraulic tenders, each pulling three open style coaches.

Each coach can accommodate up to 21 seated passengers in a forward facing configuration, providing an excellent overall capacity per train of 63.

Wheelchair accessibility has also been incorporated into one of the carriages on each train meaning all visitors to the zoo are able to enjoy the experience.

The trains run continuously on a 1.2 mile oval track around the zoo's perimeter and each ride take approximately 17 minutes.

The venue has employed more than a dozen workers to operate the train service, all of whom are trained as engineers, conductors and station managers.

The three positions are regularly rotated and all the members of the team who will work on the trains have been trained by amusement industry consultant Ken Vondriska.

"We are delighted to announce the delivery of these two new trains to Louisville Zoo," said Severn Lamb managing director, Patrick Lamb.

"The resumption of the train rides comes four years after a derailment of one of the zoo's previous trains so not surprisingly they looked long and hard at which supplier to choose when looking for replacements"