How do I import raw data like:

   1 "4072     400"  0  0  2 1.0280 -10.70 2000.000 500.0000 1332.970 406.026 400.000 1.0280 1000.00 -300.00 0.00000 0.00000    0
   2 "4071     400"  0  0  2 1.0330 -5.241 300.0000 100.0000 469.9895 86.6269 400.000 1.0330 250.000 -50.000 0.00000 -4.0000    0
   3 "4011     400"  0  0  3 1.0500 0.0000 0.000000 0.000000 437.3903 -93.741 400.000 1.0500 500.000 -100.00 0.00000 0.00000    0
   4 "4012     400"  0  0  2 1.0400 2.4097 0.000000 0.000000 600.5866 -134.52 400.000 1.0400 400.000 -160.00 0.00000 -1.0000    0
   5 "4021     400"  0  0  2 1.1000 -22.22 0.000000 0.000000 281.9937 -30.000 400.000 1.1000 150.000 -30.000 0.00000 0.00000    0
  
...

It is not that difficult as the set elements with the blanks are quoted. Just introduce column names and import the data into GAMS using $ondelim and $offdelim:

table x(*,*,*)
$ondelim
a,b,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16
   1 "4072     400"  0  0  2 1.0280 -10.70 2000.000 500.0000 1332.970 406.026 400.000 1.0280 1000.00 -300.00 0.00000 0.00000    0
   2 "4071     400"  0  0  2 1.0330 -5.241 300.0000 100.0000 469.9895 86.6269 400.000 1.0330 250.000 -50.000 0.00000 -4.0000    0
   3 "4011     400"  0  0  3 1.0500 0.0000 0.000000 0.000000 437.3903 -93.741 400.000 1.0500 500.000 -100.00 0.00000 0.00000    0
   4 "4012     400"  0  0  2 1.0400 2.4097 0.000000 0.000000 600.5866 -134.52 400.000 1.0400 400.000 -160.00 0.00000 -1.0000    0
   5 "4021     400"  0  0  2 1.1000 -22.22 0.000000 0.000000 281.9937 -30.000 400.000 1.1000 150.000 -30.000 0.00000 0.00000    0
...
;
display x;

and you will get:

----     46 PARAMETER x  

                          3           4           5           6           7           8           9          10          11

1 .4072     400       2.000       1.028     -10.700    2000.000     500.000    1332.970     406.026     400.000       1.028
2 .4071     400       2.000       1.033      -5.241     300.000     100.000     469.990      86.627     400.000       1.033
3 .4011     400       3.000       1.050                                         437.390     -93.741     400.000       1.050
4 .4012     400       2.000       1.040       2.410                             600.587    -134.520     400.000       1.040
5 .4021     400       2.000       1.100     -22.220                             281.994     -30.000     400.000       1.100