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8. Average Number of Bypasses per Damaged Bridge on Selected Rail Lines 50
 9. Maximum Repair Times at Selected Bridges on Selected Rail Lines in North Vietnam 52
 10. Bypasses and Other Countermeasures on Rail Lines in the Northern Part of North Vietnam 55

Illustrations

Figure 1. Rolling Thunder Attack Sorties, by Route Package, January - August 1967 (map) following page 6
 Figure 2. North Vietnam: Continuity and Intensity of Attacks on Railroads (chart) following page 8
 Figure 3. North Vietnam: Improvements to the Basic Transportation Net Since March 1965 (map) following page 14
 Figure 4. Hanoi - Haiphong (map) following page 18
 Figure 5. Northeast North Vietnam (map) following page 18
 Figure 6. Estimated International Traffic Carried on North Vietnamese Railroads, 1964 and August 1967 (map) following page 34
 Figure 7. Estimated Military and Civilian Supply Requirements, by Area (map) following page 42

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