Definition of "touchiness"

The engine seemed a little sensitive to wet rails, and in consequence the uphill work was not so good north of Dundee as it had been earlier. But I have noted this same "touchiness" on the part of the "A4s", and other modern British 4-6-2s, so that in this respect No. 2006 proved no exception.

1947 January and February, O. S. Nock, “"The Aberdonian" in Wartime”, in Railway Magazine, page 9