| Present Location | Ecclesbourne Valley |
| County Location | Derbyshire |
| Designed For | BR |
| Build Location | Derby |
| Built by | BR |
| Diagram number | 514 |
| Lot number | 30380 |
| Type | DMBS |
| First Number | 79900 |
| Later Numbers | M79900 RDB975010 IRIS |
| Present Number | M79900 |
| Current Livery | BR multiple unit green livery |
| Gauge | 4ft 8 1/2in |
| Wheel Arrangement | 4-w bogies |
| Original Underframe | Yes |
| Original Bogies/Wheelsets | Yes |
| Additional Notes | One of only two cars, converted as two experimental single unit cars from a Derby Lightweight twin unit under construction. Used on Buckingham to Banbury service 1956 to 1961. W 1967, then to BR Research as Test Car "Iris". P Butterley 2000. Restored to original appearance (inside and out). Seats carry later BR moquette. To Ecclesbourne Railway at Wirksworth by 07/08. |
| External Structural Condition | Good |
| Internal Structural Condition | Good |
| Underframe Condition | Good |
| External Finish | Good |
| Internal Finish | Good |
| Degree of External Originality | Some replaced/reproduced material |
| Degree of Internal Originality | Some replaced/reproduced material |
| Degree of Underframe/Running Gear Originality | As left Departmental service |
| Degree of External Authenticity | Very Good |
| Degree of Internal Authenticity | Very Good |
| Degree of Underframe Authenticity | Very Good |
| Rarity | Unique |
| Historical Importance | Very Important |
| Storage | Secure Open |
| Operating | Yes |
| Survey Date | 12/02/2012 |
| Surveyor | David Wigley |
| Photo Date | 14/04/2018 |
| Photo by | Steve West |
| At Risk | No |
| Date Record Last Updated | 08/05/2018 |
