Is this a valid AONE4 routing ?
 

HI
Hoping that one of the experts on these matters might be able to shed some light ..
Is this valid routing please ?

TYO -LHR-DXB-LHR-LAX-JFK-BDA-MIA-ORD-BUF-ORD X HKG X SIN -SYD-WLG-SYD-TYO

Many thanks
The online booking tool permits ORD X HKG SYD WLG SYD X SIN X TYO but not the one above ....

No, your itinerary is not valid
You have two departures/arrivals in Asia, and so your itinerary must comply with this ruleYour itinerary has:

• A departure from Asia at the beginning (TYO-LHR)
• An arrival in Asia at the end (SYD-TYO)
• another Arrival/Departure in the middle (ORD-xHKG-xSIN-SYD)

This last one is not the required "transfer without stopover" because it has an intra-continental flight segment (HKG-SIN)
Contrast this with your other itinerary - ORD-xHKG-SYD which is valid because it has the required transfer without stopover in HKG

In the past I have had transit without stopover in Asia utilising this exception but including intra-Asia flight(s). I don't think this particular rule has been changed since, although possible interpretation by airlines has changed.

I just realized that I should have put that HKG SIN SYD is all transit - ie not stopping over
Does this make any dfiference to things ....?

Well if you were stopping over in either HKG or SIN (meaning longer than 24hrs in either) then for sure that would be invalid because it is then no longer "a transit without stopover".

Kiwi Flyer says he's managed to do what you are planning, which surprises me because I don't see two transits constituting "a transit without stopover" I tried doing it in the on-line tool and it disallows it. But this might be a case of YMMV if you try it via an agent or an airline

I'm pretty sure I've also done this through the oneworld online RTW booking tool. But not recently - the lack of QF flights operated by Jetconnect on the online tool has meant no recent bookings on the tool.

I just tried doing it in the online tool again
The first try (see two posts up) was with an ex-Asia itinerary, to match what the OP was trying to do)
This second try was on an ex-Europe itinerary (LHR-xHKG-xSIN-SYD-oHKG-JFK-LHR). Still no go.

As an aside - I priced up the itinerary (without the xSIN transit so as to make it valid) using both CX as the first carrier and then using BA. BA was GBP370 more expensive than CX.

FWIW, several years back I also did an xONEx which have two transit segments -- I see no issue with that and the rules as long as they are both transit -- ticketed by the AA RTW desk. Two xONEx's if I recall correctly. Haven't tried to do it since. Seem the rules are now being interpreted differently in at least some cases. May be worth pushing if ticketing via an office and it's important to you.

Same here. A few years back the transit thru Asia had an extra segment (with no stopover in Asia). The rules have not changed, so hopefully it still should be possible.