With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Gustave Eiffel focused on meteorology research.
text_B: Thames Turbo may refer to two related classes of diesel multiple unit trains built for British Rail , the United Kingdom 's then state owned rail operator , between 1990 and 1993  :. diesel multiple unit. diesel multiple unit. British Rail. British Rail. United Kingdom. United Kingdom. British Rail Class 165 , in service with both Chiltern Railways and First Great Western. British Rail. British Rail. British Rail Class 165. British Rail Class 165. British Rail Class 166 , a faster air conditioned variant of the 165 in service with First Great Western. British Rail. British Rail. British Rail Class 166. British Rail Class 166
not_related.