Percent

January-May

June-August

Hanoi - Yen Vien 4.0 5.4
 Yen Vien - Lao Cai 24.5 68.5
 Yen Vien - Dong Dang 17.2 43.5
 Gia Lam - Haiphong 2.0 28.3
 Kinh No - Thai Nguyen 9.9 39.1
 Thai Nguyen - Kep 6.6 33.7
 Railroads north of the 20th Parallel 37.7 84.8
 Hanoi-Vinh 88.7 94.6

The campaign against railroads has accounted for
 13 percent of the Rolling Thunder attack sorties flown
 during January-August 1967. Aircraft losses sustained
 in these attacks totaled 41, or 18 percent of total
 US combat losses during January-August 1967. A
 share amounting to 68 percent -- 28 aircraft -- was
 downed in June-August alone. This disproportionate
 loss rate reflects the higher risk to aircraft attacking
 railroads in heavily defended areas.

Thus, while the overall combat loss over North
 Vietnam during these eight months was 3.0 aircraft
 per 1,000 attack sorties, the campaign against railroads
 resulted in a combat loss rate of 4.0 aircraft.
 During the June-August period, attacks against railroads
 resulted in a loss rate of 4.7 aircraft. The
 loss rate for attacks against northern rail lines
 alone during this period was even higher -- 6.3 aircraft
 per 1,000 sorties -- although it was down somewhat
 from the loss rate of 6.9 for all attacks in
 1967 against the northern rail lines.

The scale of attack against North Vietnam's
 railroads during 1967 is indicated by a comparison
 with the number of attacks against all other JCS-targeted
 facilities. These targets, which include
 electric powerplants, manufacturing and explosives
 plants, petroleum storage facilities, airfields,
 barracks, supply and ammunition depots, and radar

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