MK X or MKX1 sticky this one ! as both introduced in 1905 at a cost of £60, i believe they were all tagged as MKX , grounded on ive never seen a mkx1 tag and the original (copy) of manufactures detailed drawing i have shows clearly pros/bronze dust caps but dated 1915 and marked war office Drawing, wagon ,general service mkx, i know there is earlier one in private ownership without dust caps, i guess the naves or the wheels may have been upgraded during service on most wagons !