The case for a third single circle Train Mail cancel

I previously showed some used stamps with a difficult to fit Train Mail postmark. Recently, I acquired a group of similar stamps and repeated the exercise with the same results.

This cancellation fits D10 quite nicely, Curiously, it has exactly the same date of 11 JUN 62 which was the first recorded date for a Proud D10.

 A Train Mail cancel which fits well with a Proud D9 with the date of 21 NOV 59.

On piece, we have a 1954 QE 10c stamp but unfortunately not the "extra chimney" variety but an almost complete Train Mail with the date of 7 SEP ??.

This postmark is not a D10 but does not fit D9 by a significant margin. It has the date of 12 AUG 58.

But it fits the postmark on piece very well. It looks like these two used stamps has a SC Train Mail cancellation which is yet to be classified.

This is confirmed by the above measurements. The D9 and D10 from Proud's standard reference both measures 25mm. My proposed third SC Train Mail postmark on the two items on piece both measures 26mm. Please also take note how the line drawn from the second leg of the letter "N" in TRAIN transects the letter "B" in BORNEO.