Protection of troop and freight trains is determined by such weapon disposal as best assures
the safe arrival of the train with the minimum of losses. The following article, reproduced
by permission of the British Air Ministry, contains information which supplements that
reported in Tactical and Technical Trends, No. 5, p. 7.
a. Equipment for Defense of Trains
The normal Flak gun for the defense of trains is the 20-mm; machine guns
are also used. It is possible that the 37-mm gun may sometimes be
used, though this is not known for certain. The accompanying sketch shows
a 20-mm railway Flak detachment.
An open freight car is the type commonly used for the 20-mm gun according
to the German manual. The gun can be accommodated at one end, and the crew under a
removable roof at the other; alternate positions are provided at either end of the
car so that the gun position and crew shelter can be reversed, if necessary.
The muzzle-brake is removed from the 20-mm gun to reduce the length of the barrel. Safety
fences on all four sides of the gun insure that it is not fired below the safety
angle. These measures make it impossible for the gun to strike obstructions such as
tunnels, signal posts, or other trains. Other safety measures include the posting
of look-outs to prevent firing which might damage telegraph wires, signal posts,
tunnels, or other obstructions, and a complete prohibition of firing on electrified
lines with overhead cables.
Photographic evidence suggests that, in practice, converted passenger coaches and
roofed freight cars with part of the roof removed are often used instead of
freight cars--a measure probably dictated by the need to economize in specially
It is understood that the allotment of Flak cars per train is as follows:
(1) Three cars mounted with machine guns placed a quarter, a half, and
three-quarters of the way along the train.
(2) Three cars carrying 20-mm light Flak guns: one in the middle of
the train, one at the rear, and one immediately behind the locomotive. The gun
behind the locomotive is not manned, being a spare to permit reversing the
train without shunting the guns.
(3) On especially important trains an additional 20-mm gun is
carried on a car in front of the locomotive.
In practice the allotment of Flak cars varies considerably, and it is probable
that the full allotment is rarely allowed. A recent report stated that on
French railroads two Flak cars, instead of the usual allotment of one, were to
be run at the rear of all trains in use by the armed forces; on the other
hand, in many cases an allotment of as little as one gun to a train is made.
Examples of trains (believed to be military) photographed in France are
(1) Engine, 5 passenger coaches, 5 box-cars, Flak car, 12 box-cars, 5 flat
cars, 3 box-cars, 8 flat cars;
(2) Engine, 4 passenger coaches, 14 flat cars, Flak car, 25 box-cars;
(3) Engine, 23 flat cars, 5 box-cars, Flak car, 3 passenger
coaches, 2 box-cars, 16 flat cars, 1 open car, 2 flat cars, and 1 box-car.
It is of interest that, in most cases in these examples, the Flak car is
preceded or followed by box-cars, which must presumably hinder somewhat the
field of fire.
On the move the guns, continuously manned, are allotted 180° priority
arcs as follows:
(1) Forward--the front MG and center 20-mm guns;
(2) Rearward--the center and rear MG's and the rear 20-mm gun;
(3) Forward--the 20-mm gun in front of the locomotive (when carried).
When the train is stopped, the guns may be moved from the cars and
deployed on the ground so as to give a better field of fire. The decision to do this
naturally depends on the probable length of the halt.
c. Protection of Ground Areas and Lines of Communication
In many parts of Germany and also, it is believed, elsewhere (especially in
Russia), mobile heavy and light Flak units are employed with guns on railway
mounts. They may be equipped with any of the following
calibers: 20-mm (single or four-barrelled), 37-mm,
75-mm, probably 88-mm, 105-mm, and
possibly 150-mm. These units move from place to place in special
Flak trains, with their own living and kitchen accommodations. The heavy guns
are not fired on the move, though no doubt one or two of the light guns are
manned for defense of the train. On arrival at their destination the trains
are broken up, and the guns and equipment sited on sidings.
Considerable reliance is placed by the Germans on these railway Flak units as a
means of providing rapid reinforcement to threatened areas. Air reconnaissance
has shown that frequently railway Flak has been moved to ground defense
areas after a heavy RAF attack, in the expectation of further attacks on
subsequent nights. Instances have also been reported of the employment of
railway Flak at objectives where, for reasons of expediency, no permanent
Flak protection is provided.
Apart from the reinforcement of ground defense areas, railway Flak units
are used, especially in theaters of active operations, for mobile protection of
railway communications. For this purpose light guns are apparently considered
of most value, presumably since stations, junctions, loading bays, and sidings
are particularly vulnerable to low-flying attack.
Heavy railway Flak units identified from air photographs normally consist
of four heavy Flak cars, two light Flak cars, and a command group. The
command group comprises cars of a special type, often four in number, one of
which carries the Kommandogerät (director and rangefinder) and a second, in
some cases, equipment for remote fire control. The purpose of the remaining
two cars is not entirely clear; one is possibly a plotting and control unit for
the use of the gun position officer (battery executive) and the other may in some
instances carry a searchlight. In many instances the command group is confined
to two cars. These may correspond with the first two cars of the four-car
command group, though it is not unlikely that they may be associated with units
equipped with the lighter auxiliary fire-control instruments only, one car
carrying the auxiliary director and the other the rangefinder. In addition to the
operational cars there are several coaches which provide accommodation for
So far as the limitations imposed by the railway tracks permit, an effort
is made to lay out the gun positions in the normal manner. The heavy Flak
cars are usually sited on the unoccupied tracks of a siding at the corners
of a rectangle, the long sides of which generally vary from about 40 to
80 yards. The command group is sited at one end of the position, some
100 to 300 yards distant, and the light Flak cars generally at either
end of the position. A position of this type is shown in the sketch on the
When only a single siding is available, the heavy Flak cars are sited
along it at intervals of 40 to 50 yards, the remainder of the position
being similar to the type described above.
There appear to be two main types of heavy and one main type of light Flak
cars. Their dimensions and construction are shown in the accompanying
sketches; since the measurements are obtained solely from photographic
interpretation, they are subject to a margin of error of 10 to 15 percent.
The extension to the center part of the broad-type heavy Flak car (outside
the dotted lines in the sketch) is clearly shown by photographic evidence to
be a folding flap. It is highly probable that the platform surrounding the raised
portions is also capable of being folded or detached when in transit, since the
movement of a 15-foot vehicle would be impracticable, except
possibly on special sections of a railroad. The raised portions are
about 2 to 3 feet above floor level; it is of interest that, whereas they
are surrounded by a platform in the broad-type car, they extend the whole
width of the narrow type.
Railway Flak units are organized into regiments, battalions, and batteries; the
precise composition of the units is not known. It is believed that the
regimental organization forms a pool from which units may be drawn as the
necessity arises, either for mobile defense or for train protection. The unit
most frequently met with is the battery, which in mobile defense probably moves
and operates as a unit; in the case of train protection, the battery headquarters
presumably administers detachments allocated to different trains. Although
railway Flak units are part of the German Air Force and are administered through
the usual GAF channels, it is probable that train protection detachments are
operationally subordinate to the transport authorities; there is some evidence
that guns provided for the protection of military trains may in certain
circumstances be manned by army personnel.