Czechoslovak Border Fortifications MO-S 19 ‘Alej’

MO-S 19 ‘Alej’ is a beautifully restored example of the Czechoslovak border fortifications built in the mid to late 1930s to defend the country against Hitler’s Germany. Alej was built in 1936.

‘MO’ stands for Moravian Ostrava, ‘S’ for ‘Srub’ or blockhouse. 19 means the 19th blockhouse in the line and the code-name ‘Alej’ means ‘Alley’, probably after the tree-lined road which passes by.

Most of the blockhouses and pillboxes which were built by the Czechslovakian government between 1935 and 1938 still exist, although most of them are ruins. This makes MO-S 19 such an important historical monument because it has been restored to its original 1938 fighting condition.

After the Munich Treaty gave the Sudetenland to Hitler, these bunkers were stripped of their armoured cupolas and loopholes. They were made from the highest quality Swedish iron ore by the Vitkovice steelworks, one of Europe’s leading steelworks at the time. Vast amounts of explosives were used to remove the steel from the concrete, leaving the buildings ruined.

This was the condition of MO-S 19 in the 1980s, a ruined pile of concrete. If you look at the nearby MO-S 20 ‘Orel’ (Eagle) blockhouse, you will see what MO-S 19 was like.

MO-S 19 ‘Alej’ Contents

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MO-S 19 ‘Alej’ – Fighting Floor Plan

Plan of the fighting floor of MO-S 19 'Alej'

Plan of the fighting floor of MO-S 19 ‘Alej’

      • L1 – Single heavy machine gun, ZB 37 or 35, 7.92mm, dual-mounted with anti-tank cannon, Skoda 36, 47mm.
      • M – Twin heavy machine guns, ZB 37 or 35, 7.92mm.
      • ZN – Armoured bell for single light machine gun, ZB 26, 7.92mm
      • KM – Armoured cupola for twin heavy machine guns, ZB 37 or 35, 7.92mm.

MO-S 19 ‘Alej’ – Photo Gallery

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MO-S 19 ‘Alej’ – Restoration

The two small observation cupolas were taken from other blockhouses (OP-S 28 and 29 in the Opava sector) and the twin machine gun cupola came from R-S 75 ‘U křížku’ (‘At The Crossroads’) in the Orlicky Mountains. The missing armoured loopholes came from various blockhouses around Milostovic, near Opava.

The interior equipment and fittings are also restored to their original state. All the cupolas have firing platforms installed, mounted on a central column. The columns could move up and down to allow the weapons to fire at different angles and contained a disposal chute for empty cartridges as well as smoke ventilation equipment. Visitors can also see a complete ventilation/air filtration system, a signalling system and an electrical distribution network. The air filter and diesel generator for electricity were built after the war but they show how the systems were integrated into the design of the blockhouse.

Two other very rare items are the twin heavy machine guns mounted in the M loophole and a specially refurbished, original anti-tank cannon in the L1 position, which is one of only two in the whole country. Originally, it was intended for the entrance building of the Stachelberg artillery fortress in North Bohemia but it was never built. Instead, the Germans mounted it in one of the remaining armoured loopholes in OP-S 29 in the Opava sector for use against the advancing Red Army. The bunker was eventually blown up in 1945 and the cannon lay in the ruins until 1968.

MO-S 19 ‘Alej’ – Current Condition And Equipment

The exhibition of equipment inside MO-S 19 is a fantastic display of attention to detail. Walking in through the 450 kg main door and smelling the faintly damp concrete, mixed with machine oil is just the beginning. The tour starts in the main armament room, with the almost-unique Skoda 36 47 mm anti-tank cannon. If there are not too many people, you can stand in the firing position and look through the sights out into (today) the car park. Immediately, you notice the clear lines of fire down into the anti-tank ditch. Slightly up the hill, you can clearly see MO-S 18 ‘Oboru’, the neighbouring blockhouse, which was designed to house the same anti-tank cannon, aimed back at MO-S 19.

The twin heavy machine guns to the right of the cannon have a restored blind firing indicator. This is a panoramic sketch of everything in the arc of fire with a needle attached to the gun mount. As the weapons are moved around, so the needle moves, indicating where they are aimed. The Czechoslovakian army expected a night attack and all of the blockhouses and pillboxes were linked by a telephone system. This allowed spotters in other positions to direct fire at the enemy.

A selection of cannon rounds, shells and a bomb are also on display. I was amazed to hear that entrance door was designed to withstand a direct hit by the huge shell. Likewise, a direct hit with the bomb (it looked like the 250 kg bomb carried by Stukas but I’m not sure) was expected to make a 60 cm dent in the 2.5 metres of concrete which made up the roof.

Other loopholes in the walls are fitted with observation ports. They feature a circular steel plate with thick glass and a slit for observation. The slit was narrower than the calibre of rifle and machine gun rounds for protection against direct hits. The whole plate could be removed to allow a type 26 light machine gun to be mounted in its place for close defence. These weapons are displayed in their racks next to the observation ports.

A periscope extends outside the walls by the defensive ditches (known as diamond ditches because of their shape) and chutes angled down through the walls so that the defenders can roll grenades outside. The defenders had half a million machine gun rounds and enough food for 2 weeks. The boxes of food and ammunition are stacked in almost every free space you see as you walk around – under stairs, tables, around beds and in corridors.

The tour continues past the telephone and radio rooms and past the steps up to one of the armoured cupolas. Again, the restoration is complete. The ammunition hoist leads up to the top and the central pillar coming down from the firing platform contains an extraction system to ventilate gunsmoke as well as a chute for spent cartridges. The platform itself was pneumatically operated, allowing the defenders to raise and depress the weapons without standing or squatting – they simply raised or lowered the platform. In addition, there was a periscope for all round observation, which helped the defenders to observe and direct fire from other blockhouses.

On the lower floor, you can see the cramped sleeping quarters for the crew of 36 soldiers, crammed with ammunition and food boxes and the generator/ventilation pump room. The diesel aggregate unit and ventilation system on display was actually built after the end of World War Two but is the same type as the one originally installed. These allowed the defenders to be self-sufficient for electricity and to have breathable air in the event of poison gas attack or heavy, sustained gunfire.

Here you can also see the pump for the well, which was bored 47 metres down to provide fresh water for drinking and cooling the diesel motors.

All in all, this museum represents an important piece of European history. The Czechoslovakian Borer Fortifications were never finished so we will never know if the Nazis could have been stopped at the border. As with all of the bunkers around Ostrava, the only time they were used in wartime was when the Red Army were advancing in the final months of the war. The Germans repaired the damaged loopholes with concrete to replace the hard steel embrasures which they had removed. However, they had also removed the heavy weapons to build the Atlantic Wall and, at the cost of around 3000 men per week killed, the Red Army finally overran the Germans in late April/early May 1945.

If you would like more information or a tour of MO-S 19, you can contact me here. The tour takes about 30 minutes and costs 50 CZK – a little less than 2 Euros. Unfortunately, it’s only available in Czech but I’m working on a translation of the guide’s script and until then, it’s mostly a visual experience anyway!

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