»thumble-rigged

I came across the expression "thumble-rigged" in a twenty-five year old book on the New York City subway, but do not find any online references to the expression, nor any reasonable usage of thumble itself. The context of the phrase suggested a meaning not along the lines of jerry-rigged or its predecessor, jury-rigged, but something more like "built by influence".

salim filed this under lingo at 14h06 Sunday, 30 September 2007 (link) (Yr two bits?)