MO-S 5 Na trati casemate

MO S-5 "Na trati" is an armored infantry blockhouse in Bohumín, standing in the Starý Bohumín district right by the Czech-Polish border. Built between 1935 and 1938 as part of the Czechoslovak border fortification system, it's one of the more unusual military relics in the Karviná region.

What is this place?

The bunker was concreted in the summer of 1936, during the first construction phase of the Czechoslovak fortified line along the Silesian border. It sits next to the railway line running from Bohumín to Chałupki, close to the D47 motorway and route 58 — precisely where military planners in the 1930s expected the most likely direction of an attack along the Oder valley.

Its name, "Na trati" ("by the track"), is no coincidence. A high railway embankment cutting across the site made it impossible to cover the ground effectively from a single position, so engineers designed the fortification as two separate, symmetrical structures linked by an underground corridor running beneath the embankment itself. This layout is unusual even among Czechoslovak border fortifications, and it's what makes MO S-5 stand out from the many bunkers scattered across the region.

What will you see?

Visitors can walk into both halves of the bunker and through the connecting tunnel underneath the railway line — a rare chance in the region to see firsthand what daily life and duty looked like for a fortification crew. Original fittings survive inside, and the site is run by the local military history club (KVH Bohumín), which has spent years restoring the structure and now operates a small museum dedicated to the history of Czechoslovak border defenses.

The bunker never actually saw combat in the way it was built for. After the Czech borderlands were occupied in autumn 1938, the structure was taken over by Polish troops, and in 1939 it was occupied by German forces without a fight. During the occupation, its armored observation cupolas and gun-port shields were stripped out — their absence is still visible in the structure today, a quiet testament to the turbulent history of this borderland.

How to get there?

Bohumín sits right on the Polish-Czech border and is well connected by road and rail from both Ostrava and the Polish side around Racibórz and Chałupki. The bunker stands in the Starý Bohumín district, directly next to the railway line — the easiest approach is by car or train to Bohumín, followed by a short walk. Since the site is run by a volunteer club, it's worth checking current opening hours in advance, as the exhibition tends to operate seasonally or on selected days.

When to visit?

Spring through early autumn is the best window, when the volunteer-run museum keeps more regular hours. It's a worthwhile stop for anyone interested in WWII history and Central European border fortifications, and fits naturally into a longer trip along the Czechoslovak fortification line around Ostrava.

Frequently asked questions

What is MO S-5 "Na trati"? It's an armored infantry blockhouse from the 1935–1938 Czechoslovak border fortification system, built in the summer of 1936 in Bohumín, consisting of two structures linked by an underground tunnel beneath a railway embankment.

Can you go inside? Yes, the site is open to visitors as a museum run by a local military history club, though opening hours can be limited seasonally.

Did the bunker ever see combat? No — it was occupied by Polish troops in 1938 and then by German forces without resistance in 1939, who stripped out its armored fittings.

Why does the bunker have such an unusual layout? The high railway embankment blocked effective fire from a single position, so it was built as two symmetrical structures joined by an underground corridor running beneath the tracks.