Perhaps you should try some spelling variations:
"electric multiple unit" » "electrica multiple unit", "electrico multiple unit", "electricos multiple unit"
"electric multiples unit" » "electrica multiples unit", "electrico multiples unit", "electricos multiples unit"
"electric multiple units" » "electrica multiple units", "electrico multiple units", "electricos multiple units"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("electric multiple unit") OR ("electric multiples unit"))) OR ("electric multiple units"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"electric multiple unit\") OR (\"electric multiples unit\"))) OR (\"electric multiple units\"))".
• Removing quotes may allow a broader search: (((( electric multiple unit ) OR ( electric multiples unit ))) OR ( electric multiple units )).
• Adding a wildcard symbol may retrieve word variants: (((("electric multiple unit") OR ("electric multiples unit"))) OR ("electric multiple units"))*.