Elecrail's operational Swingdoor/Dogbox set made up of 107M and 137M rests inside the Newport Workshops, alongside unrestored driving trailer 24D. 107M was built as a steam hauled suburban car in 1888, and modified for electric use in the early 20th century. All three of these cars (along with another D car, 32D) made up the consist of the last Dogbox train to operate in revenue service, in 1974. Due to on-going accreditation issues these classic EMU's have not been able to run on the mainline since 2004, but it is hoped that this will be resolved in the next couple of years.
[UPDATE:] The cars in this image were tragically completely destroyed by fire in 2015. See photo No. 521628 for more information.