Trainz is measured in Meters.
You can use the paste height to make a baseboard a flat height, or apply displacement maps in terrain.
What you will achive is steps, if you apply heights as you mentioned.
Many many repetitive tracks, placed at 20m (two grid lines apart) will help level the two different height baseboards, by hitting the "Smooth Spline" tool.
It seems the magic number to divide by, is roughly @ 3.28
Numbers rounded off to simplify things.
Imperial height elevation (ft) above sea level = Metric in Trainz (m):
2200' = 671 m
2180' = 665 m
2160' = 659 m
2140' = 652 m
2120' = 646 m
2100' = 640 m
2080' = 634 m
2060' = 628 m
2040' = 622 m
2020' = 616 m
2000' = 610 m
1980' = 604 m
1960' = 598 m
1940' = 591 m
1920' = 585 m
1900' = 579 m
1880' = 573 m
1860' = 567 m
1840' = 561 m
1820' = 555 m
1800' = 549 m
1780' = 543 m
1760' = 537 m
1740' = 530 m
1720' = 524 m
1700' = 518 m
1680' = 512 m
1660' = 506 m
1640' = 500 m
1620' = 494 m
1600' = 488 m
1580' = 482 m
1560' = 476 m
1540' = 469 m
1520' = 462 m
1500' = 457 m
1480' = 451 m
1460' = 445 m
1440' = 439 m
1420' = 433 m
1400' = 427 m
1380' = 420 m
1360' = 415 m
1340' = 408 m
1320' = 402 m
1300' = 396 m
1280' = 390 m
1260' = 384 m
1240' = 378 m
1220' = 372 m
1200' = 366 m
1180' = 360 m
1160' = 354 m
1140' = 347 m
1120' = 341 m
1100' = 335 m
1080' = 329 m
1060' = 323 m
1040' = 317 m
1020' = 311 m
1000' = 305 m
980' = 299 m
960' = 293 m
940' = 286 m
920' = 280 m
900' = 274 m
880' = 268 m
860' = 262 m
840' = 256 m
820' = 250 m
800' = 244 m
780' = 236 m
760' = 232 m
740' = 226 m
720' = 220 m
700' = 213 m
680' = 207 m
660' = 201 m
640' = 195 m
620' = 189 m
600' = 183 m
580' = 177 m
560' = 171 m
540' = 165 m
520' = 159 m
500' = 152 m
480' = 146 m
460' = 140 m
440' = 134 m
420' = 128 m
400' = 122 m
380' = 116 m
360' = 110 m
340' = 104 m
320' = 98 m
300' = 91 m
280' = 65 m
260' = 79 m
240' = 73 m
220' = 67 m
200' = 61 m
180' = 55 m
160' = 49 m
140' = 43 m
120' = 37 m
100' = 30 m
95' = 28.96 m
90' = 27.44 m
85' = 25.91 m
80' = 24.39 m
75' = 22.87 m
70' = 21.34 m
65' = 10.82 m
60' = 18.29 m
55' = 17.77 m
50' = 15.24 m
45' = 13.72 m
40' = 12.20 m
35' = 10.67 m
30' = 9.15 m
25' = 7.62 m
20' = 6.10 m
15' = 4.57 m
10' = 3.04 m
9' = 2.74 m
8' = 2.43 m
7' = 2.13 m
6' = 1.82 m
5' = 1.52 m
4' = 1.22 m
3' = 0.91 m
2' = 0.61 m
1' = 0.30 m
6" = 0.15 m
3" = 0.91 m