There are six old tenders found on the North Western Railway. They are described as being very old, dirty and filled with boiler sludge.
The tenders were seen being shunted by Diesel on the other railway.
Two tenders were once seen on a flatbed being pulled by Harvey.
Two of the tenders somehow ended up at Great Waterton with one sitting in the station when Thomas discovered the town.
In the Railway Series, the first tender was based on an LMS Fowler 3500-gallon type, whilst the second was based on an LMS Stanier 4000-gallon type. The other four tenders are LMS Fowler 3500-gallon types.
In the television series, the old tenders are all based on the LNER Gresley/Thompson 4200-gallon type.
The old tenders appear to be painted NE wartime black and LMS black, however given their age they appear faded and rusty.
- Sludge tenders were a genuine practice on the railways, particularly when the diesel era started and more LNER locomotives were scrapped leaving their tenders available for different usage.
- One of the old tenders has "LMS" on the side, a possible reference to Henry's basis; the LMS Black 5 Class. Some of the other tenders have "NE" on the sides, indicating that they are North Eastern Railway tenders.
- Since the tenders appeared all together in "Escape" after "Tender Engines", it can be assumed that they were sent for scrap after the events of the latter episode.
- One of the old tenders was used for the Halloween Engine's tender.
- It also gained a tail lamp.