On e-bay are what look like commercial GWR carriage bogies. The
vendor says the "distance between the inside of the wheels is 6.6cm"
That sounds more like 3in Gauge to me, but could they be Gauge 3? If
so, any idea of the make? If the link below doesn't work search
for "PAIR OF LARGE BRASS & DIE CAST BOGIES".

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?
ViewItem&rd=1&item=5917171961&ssPageName=STRK:MEWA:IT

Mike Williams