If my memory serves from reading about these locomotive, It didn't take long for them to be rebuilt. Like you said the motion covers were getting in the way of maintaining the joy valve gear and the slide bars, so it was taken away. The Cowling around the cab was removed as it trapped smoke and restricted the drivers view. The Coal banker at the back of the cab was too small so crews used it to hold tools and so coal bunkers were built into the pannier tanks. And later the cab was extended at the rear to cover the old coal bunker. But in service they were reliable engines and the three of them and Lyn worked well on the line.
If my memory serves from reading about these locomotive, It didn't take long for them to be rebuilt. Like you said the motion covers were getting in the way of maintaining the joy valve gear and the slide bars, so it was taken away. The Cowling around the cab was removed as it trapped smoke and restricted the drivers view. The Coal banker at the back of the cab was too small so crews used it to hold tools and so coal bunkers were built into the pannier tanks. And later the cab was extended at the rear to cover the old coal bunker. But in service they were reliable engines and the three of them and Lyn worked well on the line.