Arrangements  for  the  repair,  greasing,  overhaul,  etc.,  of  coal  wagons
were  also  largely  governed  by  the  fact  of  the  wagons  running  mainly
between  fixed  points.     Contracts  for  periods  ranging  from  one  month  to
ten,  fourteen  and  even  twenty-one  years  were  made  with  repairing  firms
who  had  set  up  extensive  works  and  engaged  large  staffs  for  the  purpose,
and  who  kept,  either  at  points  on  the  routes  taken  by  the  wagons  or  at  the
usual  terminal  points,  supplies  of  all  the  spare  parts,  axles,  springs,  etc.,
likely  to  be  required  for  the  repair  of  the  particular  types  of  wagons  in
respect  to  which  their  contracts  had  been  made.     In  the  types  of  materials
used  for  the  construction  and  repair  of  privately-owned  wagons  in  general
there  was  infinite  variety,  and  no  ordinary  firm  could  undertake  to  stock
a  complete  collection  thereof,  whether  at  its  head  establishment  or  at  its
branches.     During  the  course  of  the  discussions  which  arose  on  these  and
cognate  questions  in  1917  it  was  stated  that  of  axle  boxes  alone  over  500
patterns  had  been  scheduled.     Of  brasses  there  were  over  250  patterns.
