CKDPrahaBaldwin

CKD Praha 6S310DR diesel engine, and the Baldwin VO and 600 series engines.

I have constructed this page for any of our European railfan friends interested in the Czech T435, or T669 class locomotives which employ the CKD Praha 6S310 series diesel engines. These engines appear to be modified versions of an American diesel engine which was built beginning in the early 1930's.

The Baldwin Locomotive Works began to experiment with diesel locomotives in the 1920's, and in 1931 purchased the De La Vergne Engine Company for the purpose of designing and building a locomotive diesel engine. This engine was the Model VO, which originally had a bore and stroke of 12.5" by 15.5" and ran at 600 RPM. The 6-cylinder version developed 600 Horsepower, and the later 8-cylinder version developed 900 Horsepower. Later modifications through the 1930's resulted in a change of all VO engines to 12.75" X 15.5" and an increase in speed to 625 RPM. The 6-cylinder engine was now rated 660 HP and the 8-cylinder engine was rated 1000 HP. The 8-cylinder VO is seen at the left.

At right is a cross section view of the VO engine. Note the combustion chamber contained inside the cylinder head. This feature caused much heat to be released inside the cylinder head, and made it impossible to successfully turbocharge the engine. The change in 1946 from the VO engine to the 600 series mainly concerned changing to an open combustion chamber design, with four valves per cylinder instead of two, which allowed the engines to be turbocharged. Other serious design flaws were also addressed.

Between June and August 1945, Baldwin supplied 30 Co-Co road locomotives with 8-cylinder VO engines for shipment to the Soviet Union (Db20). The USSR did not continue to purchase parts for these units, but rather disassembled one of them and produced exact drawings for all of the parts. The Russians then produced their own supply of parts for these units. This may be the origin of the later 6S310 series by CKD Praha.

American Locomotive Company had built MRS-1 units for this purpose as well. The ALCO 539T appears to have been copied as the D50.

At left, a typical 1000 HP switcher built from 1940-1946 which employed an 8-cylinder VO diesel engine.

Following the end of the Second World War, Baldwin redesigned their engine as the 600 series. This allowed great improvement in maintenance, durability and reliability. The turbocharged 8-cylinder 608SC is seen here. This engine had the same bore and stroke as well as speed as the VO; namely, 12.75" X 15.5" and 625 RPM. The 608SC engine developed 1500 Horsepower at the crankshaft, and was later improved to 1625 HP at the crankshaft. The 1500 HP version at left was employed in the well known Centipedes, two per unit.

Further improvements were made in 1950-1951, and new labels were used for the engines. The 608SC became the 608A; the 608NA was dropped. The 606SC became the 606A, and the 606NA became simply the 606. The picture at left is the normally aspirated (non turbocharged) 606, rated 875 HP at the crankshaft, with 800 net for traction.

This is the turbocharged 606A, rated 1315 HP at the crankshaft, with 1200 HP net for traction.

All of the illustrations and performance figures on this page are taken from our collection of original Baldwin and Baldwin-Lima-Hamilton locomotive operating and maintenance manuals.

Note: the late 608A was rated 1750 HP at the crankshaft, with 1600 for traction.

Baldwin DRS6-4-15 road switcher, with 608SC engine. Rated 1500 HP. Built 1946-1950. Weight 256,000 lbs. Six axles with four traction motors (A1A-A1A.) B-B and C-C versions sold much more widely.

At left, Baldwin AS416. Built 1950-1956. 1600 Horsepower. 608A engine, rated 1750 HP at the crankshaft, 1600 HP net for traction. Weight 255,000 lbs. A1A-A1A wheel arrangement. Again, the B-B and C-C versions sold many more units.

These pictures and illustrations are only a few examples. Many locomotive models were built with various kinds of all of these engines. However, there is enough here to show the clear relationship visually between the VO and 600 engines and the Czech 6S310DR and other 6S310 series engines built in Czechoslovakia, and used all over Europe in over 8000 locomotives.

Of course, there appear to be modifications to the Czech engine. For example, versions seen in available photos and drawings feature cross flow cylinder heads, unlike those on the De La Vergne / Baldwin engines which had both intake and exhaust manifolds on the same side. Simple elbows, cast into the cylinder heads, route the intake air from what, on a Baldwin, would be the valve gear side of the engine. (The first several prototypical De La Vergne engines actually did have intake and exhaust on opposite sides.) The turbochargers on the K6S310 engines appear to be copies of the variety used on ALCO diesel engines -- perhaps, again, copied from the ALCO 539 engines known to have gone to the USSR. However, the original Baldwin specified and furnished turbocharger for the turbocharged six-cylinder engine was the Elliott BF40, which ALCO-GE was using on the ALCO 539T engine simultaneously. Only when Elliott could not supply enough of these units did Baldwin change the specification for the 606SC to the BF34; this would then make the turbocharger on the CKD/Praha engine correct, and make it originally a duplicate of the 606SC. (Other features suggest that it's likely based on this engine as well-- the extended bedplate to support the main generator, for example, which wasn't present on the vast majority of VO engines.) One difference between the Baldwin and CKD Praha engines is that of piston displacement; the Baldwin dimensions of 12.75" X 15.5" are not used, but rather a bore and stroke of 310 mm X 360 mm, which equates to 12.2" X 14.2". Still, there are enough distinctive design qualities to ensure at least some association between the Baldwin VO/600 engine series and this CKD Praha 6S310 series, however loose, and whether obtained officially through license or not.

This is a VO engine cylinder head with the valve gear cover removed. These engines are notable in their design for the employment of long connecting tubes, running from the camshaft casing on the side of the engine, up to the deck of the cylinder heads. The pushrods contained therein act on the rocker levers seen in this picture. On the VO engines, the individual fuel injection pumps for each cylinder are mounted on the camshaft housing between the intake and exhaust pushrod tubes for the corresponding cylinder. On the 600 series that follows, the pumps are not between the tubes but mounted offset to the side, as can be seen in the various pictures on this page. Much of the overall layout remained the same, however, so that the distinctive appearance remained, including the paired circular crankcase access covers with paired hold down arms.

Worldly railfan, and locomotive fan Steve Palmano has sent a great deal of material to me regarding these Czech-built engines. At left, the normally aspirated 6S310 engine. The resemblance to the 6-cylinder VO is immediately obvious.

At right, the turbocharged 8-cylinder K6S310DR. This engine roughly corresponds to the 608SC and 608A.

Left, the Baldwin-Lima-Hamilton 608A. 1750 brake horsepower, 1600 for traction. Used in the AS16, AS416 and AS616, and in the RF-16 cab and booster units. This is the final development of the engine in the US, and is the version initially also used by Cockerill in Belgium to power the Class 201 diesel locomotives built there, although on those units a Brown-Boveri turbocharger was employed instead of the Elliott H704 as seen here.

Many thanks to Steve, and all of my new railfan friends around the world for help with this research and article.