to look and to strike almost at will. German railway preparations, as a result, had to take count of three dangers: Allied air reconnaissance over the Eifel and its rail approaches, bombing attacks to knock out the Rhine rail bridges, and rail-cutting attacks stepped up to the point where repair efforts could no longer hold the pace. In the short run, decisions on the form of the air war reached in the higher Allied councils during the autumn of 1944 made the German task much easier; in the long run, these same decisions contributed to the final failure of the Ardennes counteroffensive.
British and American air leaders had found themselves consistently at loggerheads on the issue of transportation versus oil targets. The American view was that the German rail system constituted too complex a target to be demolished in any reasonable time, but that enemy oil production was so highly concentrated (particularly in the synthetic oil plants) as to permit a killing blow in the time and with the effort available. Before 16 December the American view held first priority. Indeed, during the month of October second place was accorded to attacks-subsequently judged as "rather inconclusive"-against ordnance depots, tank assembly plants, and motor vehicle production. Eventually, at the close of October, the British succeeded in raising the priority on rail attacks, although this remained second to those on oil. November was the big month for attacks against the latter, the Allied strategic air forces dropping 37,096 tons aimed at German oil production. In the second half of the month, however, the rail campaign stepped up; the Eighth Air Force and the RAF actually delivered more bombs against rail than against oil targets. The Rhine bridges presented a special problem. In November the SHAEF G-2 asked that the air mount a campaign to cut these bridges, but on this the American and British air commanders were in accord. The great Rhine bridges, heavily guarded by flak, were tough targets for the bombing techniques then current and the Allied air forces succeeded in staving off this demand.
German records, fairly full for the final quarter of 1944, give this picture of the effects of Allied air attacks. The Reichsbahn moved troop strength by rail equivalent to sixty-six divisions before the attack.  Forces equivalent to seven divisions were moved by road Twenty-seven of the division-size rail movements were affected in some wayby air attack, in most cases before they actually entered the build-up zone. Delays normally were no longer than one or two days, although from 10 December on some divisions were forced to march an extra fifty to sixty miles on foot. A number of units lost essential organic equipment during these attacks, the deprivation inevitably inhibiting their later performance. Very noticeable effects of Allied air efforts came on 10 and 11 December. On the first day a noon attack over the Koblenz rail yards left more than a hundred bomb craters. Nonetheless, the yards were in fulloperation twenty-four hours later. The main double-track line supporting theSixth Panzer Army assembly (Cologne-Euskirchen) was hit so severely as to stop all rail traffic on 11 December; but  Detailed troop movements have been worked out in Luttichau, Rail Communications, ch. VII, passim.