Hopefully this should make everything clearer.
I have retained almost all the historical border defences, there is no internal line surrounding Brussels and no Dyle Line and the Leige defences, rather than being grossly over-endowed with four lines of fortifications are only 1.5 lines here. I have worked the Antwerp fortress into the other land-based defences there. The NE border bunkers are halved and the spacing doubled from OTL figures. Going by OTL practice, the Corps HQ'd in these defended zones (4 in all) are basically manning these works and being part of them. I have not yet worked out the coastal forts in detail (excluding Antwerp), but I might have those all under naval command to draw on that source of manpower. Special fortress regiments will be attached to each Corps for the Big Forts, the small bunkers and such being normal troops. The armoured brigade at Leige will form a kind of mobile defence/ counter-attack unit which also allows me to thin the fixed AT defences too.
This is still pretty big stuff, but less big than OTL so I feel happier.
North-East Border
The border is covered by a thin screen of 118 bunkers stretched in a single line along the canals connecting Antwerp, Turnhout, Dessel, Bocholt and Lanaken. This canal line is on average 14 m wide and 2.5 m deep. The bunkers are built at the edge of the water line. To the East, where the border between Belgium and the Netherlands follows the course of the Meuse, this screen is preceded by an advanced position of twelve large anti-tank bunkers, each armed with one 60mm L/50 FRC anti-tank gun, one 13.2mm FN-Browning heavy machine gun and one searchlight. These bunkers interdict the main roads from The Netherlands into Belgium in an area were justified by just 10-15 km away from Germany behind a narrow stretch of Dutch territory.
Albert Canal
The canal (about 160 km long from Antwerp to the Meuse) has been purposefully designed as an anti-tank barrier on average 60 m wide and 5 m deep. The earth has been piled up on the western bank to give the defenders a commanding position and creating a serious physical barrier, especially in its eastern section where the banks were steep and high. In the Eben-Emael area, the canal cuts through a large hill forming an impressive gorge that would seem to preclude any assault from that side. The western bank is defenced by 85 medium machine-gun bunkers equipped with two firing ports (two 13.2mm FN-Browning). These bunkers are often built into the canal bank, spaced 1200-1400 m apart. The bunkers are aligned laterally and have overlapping fields of fire due to the long straight stretches in the canal.
To the west, the canal defences are anchored on the PFA and the east the PFL and the fort of Eben-Emael. This fort covers the potential approaches of a German assault (forces could be there within an hour) which go over bridges crossing the Meuse in Dutch territory. The fort also prevents the PFL positions from being outflanked from the north. Technically, Eben-Emael is part of the PFL but for practical reasons is integrated in the defence of the Albert canal. Eben-Emael was finished during 1935. It is manned by a garrison of 900 troops. The armament includes; one turret mounting two 120mm Cockerill-FRC M1931 guns, two retractable turrets each with two 75mm FG TR guns, twelve more 75mm FG TR in four concrete protected positions of three guns each, twelve single 60mm L/50 FRC anti-tank guns and twenty-two 13.2mm FN-Browning heavy machine guns in casemates. I Corps is assigned to defend this line.
Position Fortifiée de Liège (PFL)
This consists of a battle line about 35 km long covering Liège in a half-circle around the city about 8-9 km out. It consist of six Great War era forts (renovated 1929-31) and 62 pillboxes (built 1934/5), forming a single line in most places. 45 bunkers are of the medium dual firing ports type with two 13.2mm FN-Brownings (some have one FN-Browning and one 20mm FN-Madsen cannon for anti-tank defence). 13 artillery observation bunkers are fitted with an observation cupola. There are two large anti-tank bunkers each armed with one 60mm L/50 FRC anti-tank gun, one 13.2mm FN-Browning heavy machine gun and one searchlight, and two small anti-tank bunkers each with one 47mm L/30 gun.
The renovated forts are designed only to withstand bombardment by 220 mm artillery shells. Barchon has a garrison of 290 and is armed with; two turrets each with one 120mm Cockerill-FRC M1931 guns, two turrets each with two 105mm FG Schneider M1913, two retractable turrets each with one 75mm FG TR gun, four 50mm DBT mortars and twenty-nine 13.2mm FN-Browning heavy machine guns.
Evegnée has a garrison of 250 and is armed with; one 120mm Cockerill-FRC M1931 gun in a turret, two turrets each with one 105mm FG Schneider M1913, three retractable turrets each with one 75mm FG TR gun and twenty-five 13.2mm FN-Browning heavy machine guns.
Fléron has a garrison of 284 and is armed with: two turrets each with one 120mm Cockerill-FRC M1931 gun, two turrets each with two 105mm FG Schneider M1913, four retractable turrets each with one 75mm FG TR gun and twenty-six 13.2mm FN-Browning heavy machine guns.
Chaudfontaine has a garrison of 250 and is armed with: one 120mm Cockerill-FRC M1931 gun in a turret, two turrets each with one 105mm FG Schneider M1913, four retractable turrets each with one 75mm FG TR gun and twenty-two 13.2mm FN-Browning heavy machine guns.
Embourg has a garrison of 250 and is armed with; four retractable turrets each with one 75mm FG TR gun and twenty 13.2mm FN-Browning heavy machine guns.
Boncelles has a garrison of 250 and is armed with; four retractable turrets each with one 75mm FG TR gun and twenty 13.2mm FN-Browning heavy machine guns.
A continuous anti-tank barrier, mostly Cointet gates, ahead of the main fortifications also protects the line along with two small bridgeheads on the eastern bank of the Meuse, protecting the crossings against a German breakthrough through the main line. These bunkers are positioned to hold the roads and possible avenues for motorised attacks under their fire to delay any surprise attack on the Meuse crossings and buy time for the engineers to destroy the bridges. The anti-tank bunkers would hold the roads under their fire, the roads being obstructed by an anti-tank barrage or a crater created by engineers. The Visé bridgehead has 15 light type bunkers (one 13.2mm FN-Browning heavy machine gun) and 4 large anti-tank bunkers (one 60mm L/50 FRC). The Argentau bridgehead has 8 light type bunkers (one 13.2mm FN-Browning heavy machine gun) and 2 large anti-tank bunkers (one 60mm L/50 FRC). III Corps is assigned to defend this line.
Position Fortifiée d’Anders (PFA)
On the eve of the Great War, two concentric rings of defences protected the strategically important port of Antwerp. The Inner ring, at the edge of the city, consisted of an earth wall and a moat flanked by nineteenth century brick and mortar forts. The Outer ring formed a 94 km long arc around Antwerp about 15 km out. It was made of a string of forts and redoubts armed with artillery in steel turrets. Most works were built between 1906 and 1914 and were made of unarmed concrete. Three forts in the bends of the river downstream from Antwerp protected the city from a naval attack. Post-war the defences were left in disrepair until 1934, when Belgium decided to fortify Antwerp once again. The position has a threefold mission: protect Antwerp from a German armoured thrust through the Netherlands; secure the left flanks of the north-eastern border screen and the Albert Canal position; form a bridgehead on the Scheldt in case the army was forced to withdraw to that line.
The Outer ring was rebuilt and strengthened by anti-tank defences and layered bunker positions. The forts were renovated and repaired, but not rearmed with artillery. Each fort was converted into an infantry stronghold to be defended by a machine gun company (eight 13.2mm FN-Browning heavy machine guns and twelve 7.65mm Hotchkiss light machine guns). The heavy machine guns are deployed in modern bunkers built on top of the old turret pits where they provide flanking fire on the intervals between two works. The remaining machine guns are installed in open topped concrete positions on the fort’s glacis and inside the traditore battery and the caponnieres to defend the fort itself. Each fort is also fitted with airtight gas shelters. The smaller redoubts were converted into platoon-sized positions for one reinforced machine gun platoon (two 13.2mm FN-Browning heavy machine guns and six 7.65mm Hotchkiss light machine guns), the heavy machine guns and two light machine guns positioned in two bunkers built on the front face of the redoubt and the remainder in the traditore battery. Machine gun bunkers defend the intervals between the forts and redoubts forming two successive lines. These are standard medium type with two 13.2mm FN-Browning heavy machine guns, though some have one FN-Browning and one 20mm FN-Madsen cannon for anti-tank defence. The anti-tank defences are made up of an anti-tank ditch and a combination of flooded areas and steel obstacles. The anti-tank ditch (built 1938-1940) is 30 km long and connected the forts and redoubts of the north-eastern section of the PFA, from the mouth of the Scheldt to the Albert Canal. The ditch is 14 m wide and contains 2 m of water (can be raised to 2.5 m). It runs in a broken line, with machine gun bunkers at the inner angles. Fifteen roads cross the ditch on earthen dams with an underpass for the water and they can be quickly barred with Cointet gates. In addition, there are 33 light removable bridges to allow infantry to cross over and man the outposts of the position.
Defence against maritime attack up the Scheldt has seen most of the old forts replaced. Along the Schelde are several batteries in concrete emplacements; 1 battery of four 150mm guns, 2 batteries of four 120mm Cockerill-FRC M1931 guns each and 2 batteries of four 75mm FG TR guns each.
A powerful new fortress was completed during early 1945 with seaward defences of; four single 9.2in FRC/Vickers-Australia M1935 turrets and six single 152mm turrets. The landward approaches form a northern arc for the main PFA line with; twelve single Cockerill-FRC M1931 turrets, eight single 125mm DP turrets, eight 90mm L/50 FRC AA turrets and 16x1 37mm Schneider M1944 LAA in in concrete emplacements. V Corps is assigned to defend this line.
The Ardennes
There are a total of 321 pillboxes in the Ardennes. Of this total, 309 are light type machine gun bunkers (one 132.mm FN-Browning heavy machine gun) and 12 are medium type bunkers (all concentrated in Libramont and Neufchâteau) (1x 47mm L/30 FRC and 1x 13.2mm FN-Browning). The Ardennes works are grouped in centres de résistance (CR) to defend a town, an important cross-roads or a valley. These fortifications to allow retreating Belgian troops to delay the enemy and prevent him from outflanking any units. There are two successive strings of CRs: Vielsalm-Gouvy – Houffalize – Bastogne – Arlon on the border with Luxembourg, and, Lienne valley– Baraque Fraiture – Western Ourthe. Other CRs worthy of note are the crossroads at Neufchâteau (27 bunkers), Recogne (20) and St-Hubert (7). VIII Corps is assigned to defend this line.