Actually, it's not that uncommon on many older British track frames, since it allows the same frame to be used both on the track, and on the road for time trials (or 'tests' as they tend to be called in England).
--
Steven L. Sheffield stevens at veloworks dot com veloworks at earthlink dot net aitch tee tea pea colon slash slash double-you double-you double-you dot veloworks dot com slash
> From: "Roy H. Drinkwater" <roydrink@mac.com>
> Date: Sun, 14 Jan 2001 10:41:22 -0500
> To: classic list <Classicrendezvous@bikelist.org>, fixed gear list
> <fixed-gear@lists.davin.ottawa.on.ca>
> Subject: [CR]Holdsworth track bike on r.b.m.
>
>
> Saw this on rec.bicycles.marketplace, I've never seen a derailleur
> hanger on track dropouts before. Was this something Holdsworthy commonly
> did, or just a one-off?
>
> Note: I downloaded the jpeg and lightened / sharpened in Photoshop, but
> there's definatly a derailleur hanger there.
>
> No connection to seller, otherwise I'd be getting it!
>
> Roy H. Drinkwater
> Lititz, PA
>
>
>> Subject: FS: Holdsworth Track Frame
>> From: tanakashima@aol.com (Tom Nakashima)
>> Newsgroups: rec.bicycles.marketplace
>> Date: Sun, 14 Jan, 2001 2:43
>> Message-ID: <20010114024317.07222.00001729@ng-da1.aol.com>
>>
>> Holdsworth Track Frame (orange)
>> Size: 53cm c to t seat tube
>> 53cm c to c top tube
>> Excellent condition.
>> chrome campagnolo track dropouts rear.
>> chrome campagnolo front dropouts.
>> also has chrome rear derailleur hanger.
>> 120mm rear spacing.
>> fork and rear drilled for brakes.
>> seat post size = 27.2
>> Price: $400.oo + shipping
>>
>> view at:
>>
>> http://members.aol.com/