No, TCV like most other railway tariffs is not linear, but regressive (price rise slower, than distance). Tariff tables contains distances and corresponding price for 1st and 2nd class.
For example
------------------------------------------------------------------
|Distance, km | Full fare |Distance, km| Full fare |
| |-------------------| |-----------------|
| |2nd cl. |1st cl. | |2nd cl. |1st cl. |
|-------------+---------+---------+------------+--------+--------|
|1-10 | 2,00 | 3,00 |301-350 | 21,17 | 31,67 |
|-------------+---------+---------+------------+--------+--------|
|11-20 | 2,50 | 3,67 |351-400 | 23,17 | 34,67 |
|-------------+---------+---------+------------+--------+--------|
|21-30 | 2,83 | 4,17 |401-450 | 24,83 | 37,17 |
|-------------+---------+---------+------------+--------+--------|
|31-40 | 3,33 | 5,00 |451-500 | 25,50 | 38,17 |
|-------------+---------+---------+------------+--------+--------|
|41-50 | 3,83 | 5,67 |501-550 | 27,17 | 40,67 |
|-------------+---------+---------+------------+--------+--------|
|51-60 | 4,33 | 6,50 |551-600 | 28,83 | 43,17 |
|-------------+---------+---------+------------+--------+--------|
|61-70 | 5,00 | 7,50 |601-650 | 30,67 | 46,00 |
|-------------+---------+---------+------------+--------+--------|
|71-80 | 5,50 | 8,17 |651-700 | 32,50 | 48,67 |
|-------------+---------+---------+------------+--------+--------|
|81-90 | 6,33 | 9,50 |701-800 | 36,17 | 54,17 |
|-------------+---------+---------+------------+--------+--------|
|91-100 | 6,67 | 10,00 |801-900 | 37,83 | 56,67 |
|-------------+---------+---------+------------+--------+--------|
|101-110 | 8,83 | 13,17 |901-1000 | 40,00 | 60,00 |
|-------------+---------+---------+------------+--------+--------|
|111-120 | 9,00 | 13,50 |1001-1100 | 43,67 | 65,50 |
|-------------+---------+---------+------------+--------+--------|
|121-130 | 9,50 | 14,17 |1101-1200 | 45,33 | 68,00 |
|-------------+---------+---------+------------+--------+--------|
|131-140 | 10,17 | 15,17 |1201-1300 | 47,33 | 71,00 |
|-------------+---------+---------+------------+--------+--------|
|141-150 | 10,50 | 15,67 |1301-1400 | 49,83 | 74,67 |
|-------------+---------+---------+------------+--------+--------|
|151-160 | 11,00 | 16,50 |1401-1500 | 51,67 | 77,50 |
|-------------+---------+---------+------------+--------+--------|
|161-170 | 11,50 | 17,17 |1501-1600 | 53,17 | 79,67 |
|-------------+---------+---------+------------+--------+--------|
|171-180 | 12,00 | 18,00 |1601-1700 | 55,33 | 83,00 |
|-------------+---------+---------+------------+--------+--------|
|181-190 | 12,33 | 18,50 |1701-1900 | 59,33 | 89,00 |
|-------------+---------+---------+------------+--------+--------|
|191-200 | 14,17 | 21,17 |1901-2100 | 66,83 | 100,17 |
|-------------+---------+---------+------------+--------+--------|
|201-250 | 15,83 | 23,67 |2101-2300 | 70,33 | 105,50 |
|-------------+---------+---------+------------+--------+--------|
|251-300 | 17,83 | 26,67 |2301-2500 | 74,00 | 111,00 |
------------------------------------------------------------------
The example above is not real TCV (I don't know where to get TCV tariff tables), it is Ukrainian East-West tariff, but TCV tables should be very similar.