Loading gauge question

[richard_S]

Hoping this is the right place. What is the difference between loading gauge 6 and 6A?

 

[Boilinthebag]

Do you mean:

W6a - Lower Gauge Legacy lower sector gauge previously used for the design of freight wagons
and On Track Machines (in their running
mode).

W6a Upper Gauge - Vehicle gauge for freight wagons and On Track Machines (in their running mode)?

Can't find a reference to 6 only.

 

[Adrian Barr]

I've got this in my notes on gauging, I think it was from an RSSB document originally:

W6a

W6a is the 'workhorse' gauge of the British railway network. Following nationalisation, a standard wagon gauge (W5) was introduced in 1951, being a gauge that would fit virtually anywhere on the new 'interoperable' railway. This was replaced by W6 as a refinement, which was then replaced with W6a once issues regarding clearances to third rail electrified track were identified. It remains, to this day, the freight gauge with maximum acceptance (although not 'go-anywhere'). Note that a W6a hole will always accommodate a W6a wagon.