import os
# sample data
template = '/home/pooh/tmp/1'
all_trains = [('1_Chief', 'Trains.USSR_TovarSostav 1', '26000_Chief'),
     ('2_Chief', 'Trains.USSR_FuelCargo 1', '26001_Chief')]
  
input_filename = os.path.join(template, 'trains_way.mis')
output_filename = os.path.join(template, 'mds.mis')
 
trains_dict = dict(map(lambda x: (x[0], x[-1]), all_trains))
in_seq = False
 
inf = open(input_filename)
try:  
    outf = open(output_filename, 'w')
    try:
        for line in inf:           
            if line.startswith('['):                
                train = trains_dict.get(line.strip()[1:-6], None) # delete '[' and  '_Road]' from line for key
                if train:
                    outf.write('[%s_Road]\n' % train)
                    in_seq = True
                else:
                    in_seq = False
            elif in_seq:                
                outf.write(line)
    finally:
        outf.close()
finally:
    inf.close()