The solution of the puzzle:

 The nearest neighbour of the breakesman is one of the businessmen (Mr.X),
 and he earns exactly three times as much as the breakesman.
 => Mr.X cannot be Mr.Robinson, because he lives in Detroit.
 => Mr.X cannot be Mr.Jones, because his salary of 20.000$ cannot excactly
    be devided by three.
    => The name of the nearest neighbour of the breakesman is Mr.Smith.

 The businessman (Mr.Y) who has the same name as the brakesman, lives in Chicago.
 => Mr.Y cannot be Mr.Robinson, because he lives in Detroit.
 => Mr.Y cannot be Mr.Smith, because he is the neighbour of the breakesman,
    who lives exactly in the middle between Chicago and Detroit.
    => The name of the businessman who lives in Chicago is Mr.Jones.
    => The name of the breakesman is Jones.

 Smith beates the fireman in the billiards game.
 => The name of the fireman cannot be Jones, because he is the breakesman.
 => The name of the fireman cannot be Smith, because he beates the fireman in
    the billiards game.
    => The name of the fireman is Robinson.

       => The name of the engine-driver is Smith.
		  
	          OOOo
		___   o
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		|        D
	        -OOOO=-oo`