(12) Nothing in this article overrides the requirement to obtain scheduled monument consent  under the Ancient Monuments and Archaeological Areas Act 1979( a ).  24. —(1) The authorised tramway must be operated by electricity or, in an emergency or for the  purposes of maintenance, by diesel power or other means.  (2) The authorised tramway must be constructed on a nominal gauge of 1,435 millimetres.  (3) Where the authorised tramway is constructed along a street or in any place to which the  public has access (including any place to which the public has access only on making a payment),  the Authority must take such care as in all the circumstances is reasonable to ensure that the  authorised tramway is constructed and maintained so that the street or other place is safe for other  users.  (4) When considering what measures are required under paragraph (3) the Authority must have  particular regard to the character and usage of the street or other place and to those who could  reasonably be expected to use it.  (5) Where the authorised street tramway has been constructed in a street, works by any person  which affect or are likely to affect the Authority’s obligations under paragraph (3), including  works to any street surfaces and works affecting any equipment or apparatus placed in the street  under article 11 (power to keep apparatus in streets) must not be carried out without the consent of  the Authority, which may be given subject to such reasonable terms and conditions as the  Authority may require but must not be unreasonably withheld.  25.  Any person who, without reasonable excuse—  is guilty of an offence and liable on summary conviction to a fine not exceeding level 3 on the  standard scale.  26. —(1) The Authority may, if it considers it necessary or expedient in consequence of any  street works executed or proposed to be executed in a street along which an authorised street  tramway is constructed—  (2) The powers conferred by this article may only be exercised with the consent of the street  authority but such consent may not be unreasonably withheld.  (3) The provisions of articles 10(2) (power to alter layout, etc., of streets), 11 (power to keep  apparatus in streets), 12 (power to execute street works) and 43 (traffic signs) apply in relation to  temporary tramways laid under the powers conferred by this article as they apply in relation to  authorised street tramways.  Mode of construction and operation of tramway  Obstruction of construction of authorised works  (a) obstructs another person acting under the authority of the Authority in setting out the  lines of the scheduled works, or in constructing any of the authorised works; or  (b) interferes with, moves or removes any apparatus belonging to any person acting under the  authority of the Authority,  (a) remove or discontinue the operation of the authorised street tramway; and  (b) lay, maintain and operate in that street or in a street near to that street a temporary  tramway in place of the authorised street tramway.  Power to construct temporary tramways  ( a ) 1979 c. 46.  20