Section 44. Modification of and changes in contracts

a. The board of
  transportation for and on behalf of the city, from time to time with the
  consent, in writing, of the bondsmen or sureties of a  person,  who  has
  contracted  with  such  board  or  its predecessors to construct, equip,
  maintain or operate any  road,  may  agree  with  such  contractor  upon
  changes  in  and  modifications  of  such  contract, or of the plans and
  specifications upon which such road is to be constructed, but no  change
  or  modifications  in  the  plans  and  specifications  consented to and
  authorized pursuant to section twenty-one of this chapter shall be  made
  without  the  further  consent  and  authorization  provided for in such
  section.
    b. The board of transportation, from time to time, but only  with  the
  approval of the board of estimate and the mayor, may agree with railroad
  companies  upon changes in and modifications of the terms and conditions
  of any contract under or pursuant to which any  railroad,  or  any  part
  thereof,  has  been  or  is  to  be constructed, equipped, maintained or
  operated, and with like approval such  contract  may  be  cancelled  and
  replaced  by  a  new  contract to include the railroads embraced in such
  existing contract. The  board  of  transportation  may  include  therein
  provision  for  the  acquisition  by the city of the railroads or any of
  them or portions of any of them  and  is  authorized  and  empowered  on
  behalf  of  the  city  to accept title thereto or control thereof and to
  provide for the payment thereof through amortization or otherwise as the
  board of transportation may determine.
    c.  Any  other   provision   of   this   chapter   to   the   contrary
  notwithstanding,  the  board  of  transportation  shall not make any new
  contract  or  modify  any  contract  for  the  construction,  equipment,
  maintenance or operation of any railroad without the approval or consent
  of the board of estimate and the mayor.
    d.  If  any  contract  for  construction or equipment of a railroad or
  section thereof has been awarded and a part of the work therein required
  to be performed by the contractor has been done  or  is  in  process  of
  being  done  as  to  a  portion of the route of such road and if another
  route for a railroad has been or shall be established by  the  board  of
  transportation  under section twenty of this chapter and consented to as
  provided in section twenty-one of this chapter, which, or a  portion  of
  which,  in  the  opinion  of such board should in the public interest be
  substituted in place of a portion of  the  road  to  be  constructed  or
  equipped  under  such  contract,  then the board with the consent of the
  board of estimate and the mayor, as soon as the detailed plans  therefor
  have  been prepared as prescribed in section twenty-two of this chapter,
  without advertising  for  proposals,  may  agree  as  provided  in  this
  subdivision  with  such  contractor upon changes in and modifications of
  his contract for the purpose of making such substitution. Such agreement
  in such case may provide, in consideration, among  other  things,  of  a
  surrender  by  the  contractor  of  his  right  to  construct or equip a
  designated portion of the road or  section  or  road  described  in  his
  contract,  that  such  contractor  shall  complete  the  construction or
  equipment of the remainder of the road  or  section  described  in  such
  contract  and  shall  in  place  of the portion surrendered construct or
  equip a railroad or section of a railroad upon  such  substituted  route
  and in accordance with the plans and specifications adopted therefor for
  such  sum  of  money  as may be provided in such modifying agreement. As
  part of the consideration of such modifying agreement, the agreement may
  also provide that such contractor shall  guarantee  to  the  city,  with
  proper  and  sufficient  sureties, that in the event that the city shall
  enter into such modifying agreement providing for construction  of  such
  substituted  route or section thereof by the contractor, the cost to the

  city of providing for the construction of any additional section of such
  railroad upon such substituted route in  continuation  of  that  portion
  thereof  which  is  to  be  constructed  by  the  contractor  under such
  modifying  agreement,  shall  not be in excess of an amount specified in
  such modifying agreement or that if the contract for construction of any
  such additional  section  is  to  be  awarded  after  advertisement  for
  proposals  under  section  seventeen of this chapter, that a responsible
  bidder for the construction thereof acceptable  to  the  city  shall  be
  obtained at a price not exceeding a specified amount.
    e.  If  any  contract  for  equipment,  maintenance and operation of a
  railroad has been made and part of the work of construction thereof  has
  been  done  or  is  in process of being done, and if another route for a
  railroad has been or shall be established by the board of transportation
  under section twenty of this chapter and consented  to  as  provided  in
  section twenty-one of this chapter, which, or a portion of which, in the
  opinion  of  the  board in the public interest, should be substituted in
  place of a portion of the road to be equipped and  operated  under  such
  contract,  for  use  and  operation in connection with or as part of the
  route, a portion of which has been in part already constructed or is  in
  process of construction, then the board with the consent of the board of
  estimate  and  the  mayor may agree as provided in this subdivision with
  the person having the contract for equipment, maintenance and  operation
  of  such railroad, upon changes and modifications of such contract. Such
  agreement in such  case  may  provide,  in  consideration,  among  other
  things,  of  the  surrender  by  the  contractor  of his right to equip,
  maintain and operate a designated portion of the railroad  described  in
  his  contract, that in place of the portion surrendered, he shall equip,
  maintain and operate a railroad or  portion  of  a  railroad  upon  such
  substituted  route.  The  rental  to  be received by the city under such
  contract, as changed and modified, representing compensation to the city
  for  the  use  of  such  substituted  part  of  such  railroad  operated
  thereunder  necessarily need not be a portion of the income, earnings or
  profits from the operation of the  railroads  combined  as  provided  in
  subdivision  d  or  subdivision g of section forty of this chapter equal
  annually, if earned, to the interest and one per centum for sinking fund
  upon the amount of city bonds issued for the investment of the  city  in
  the construction thereof but may be either a specified sum of money or a
  specified  part  or  proportion  of  income, earnings or profits of such
  substituted road, or both a sum of money and a  part  or  proportion  of
  such  income, earnings or profits, or may be such portion of the income,
  earnings and profits of the railroads so combined as may be provided  in
  such  modified  contract as rental for such substituted railroad and for
  the other railroads of the city to be equipped, maintained and  operated
  under such contract as so modified.