It is thought that the ET7 class went straight into industrial service in China. Most of those reported by western enthusiasts have been employed in the steel industry. A number were rebuilt into tender engines, while others remained as tank locos all their lives. Many of the class remained in service until the 1980s and a few lasted until the mid 1990s. The last locations where working ET7s were reported were Shanghai No 1 Steelworks in 1993 and Baotou Steelworks in July 1994. Remarkably, three locos were reported stored in good condition at Baotou as late as April 2004. One loco, ET7 5333, was later plinthed at the steelworks, although not in a public area, and two more, ET7 5328 and 5332, were reported as dumped elsewhere on the site in late 2008.
The ET7s were not numbered according to the national system but are thought to have carried numbers based on their builder's number. This appears to align with Polish industrial practice and the ET7 were probably delivered with these numbers. One loco, ET7 5328 is confirmed to be Chrzanów No 5328 of 1959. However, ET7 5331 carried a plate identifying it as No 5474 of 1960 and ET7 5332 was No 5849 of 1961. It is very likely that some locos were renumbered by their Chinese owners to produce contiguous number series. The Chinese steel industry was notorious for this unhelpful practice. Locos at Shanghai No 1 steelworks were renumbered in a series from 401 upwards while those at Beijing's Capital Iron & Steel were 501 upwards.
Vital Statistics
| Class Designation | FD |
| Descriptive Name | |
| Number Series | FD 1001 - 2004, FD 2201 - 2250 |
| Builders | Voroshilovgrad |
| Building Dates | 1931 - 1941 |
| Number Built | 3200+ (1054 to China) |
| Boiler Pressure | 14.7 bar / 213 psi |
| Grate Area | 7.03 sq m |
| Total Heating Surface |
294 sq m |
| Superheater Area | 138 sq m |
| Wheel Arrangement | 2-10-2 |
| Driving Wheel Diameter |
1500 mm |
| Cylinders, Number | 2 (outside) |
| Cylinders, Diameter/Stroke | 670 mm x 770 mm |
| Valve Gear | Walschaerts |
| Tractive Effort | |
| Power Output (Wheel Rim) |
1757 kW |
| Maximum Speed | 85 km/h |
| Overall Weight | 254 t |
| Overall Length | 29.07 m |
| Coal Capacity | 22 t |
| Water Capacity | 45,400l |


