as gear 30 b via one or more interposed idler gears e g idler gear 40 as depicted in fig3 b for example such idler gear s may also rotate around an axis parallel to the axes of gears 28 and 30 referring also to fig4 in certain embodiments various components of the disclosed power train apparatus may be arranged in various ways for example gear 28 may be located between power source 20 a and transmission 22 a which may provide additional space savings or other benefits with respect to a desired power train envelope as depicted in fig4 for example coaxial shafts 24 a and 42 may allow transmission of power from power source 20 a to transmission 22 a and then from transmission 22 a to gear 28 which may be aligned coaxially between power source 20 a and transmission 22 a for example power may be transmitted from power source 20 a to transmission 22 a via internal coaxial shaft 24 a power may then be transmitted from transmission 22 a to gear 28 via external hollow coaxial shaft 42 as also described above in such a configuration various types of power sources e g internal combustion engines electrical machines and so on and various types of transmissions may be utilized the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure as used herein the singular forms u201c a u201d u201c an u201d and u201c the u201d are intended to include the plural forms as well unless the context clearly indicates otherwise it will be further understood that the terms u201c comprises u201d and or u201c comprising u201d when used.