A wide variety of wagons are used for transporting loading units by rail. They can be divided into three basic categories:
Pocket wagons for the transport of cranable semi-trailers
Pocket wagons are specially designed to carry cranable semi-trailers in Combined Transport. The wagons – they are always bogie wagons – essentially consist of two side members placed far apart with a low, short loading area to accommodate wheels as well as a semi-trailer coupling (trailer jack) that supports the front of the trailer and locks it into place. The side members are fitted with retractable locating pins to enable swap bodies and containers to be transported. This means that pocket wagons are universally suitable for all cranable loading units.
Rapid advancements in trailer technology to date have required basic changes to pocket wagons every ten years or so. This explains why there are now so many different designs. The wagon-specific requirements of trailers also vary to a corresponding extent. The main models are briefly described below.
UIC type 1a pocket wagon (“European standard pocket wagon”)
This wagon type was developed in the early 1970s by UIRR companies and railways. Universally suitable for the Combined Transport of semi-trailers and swap bodies, it was bought by a number of railways and operators and is still in use today to some extent. The relatively low weight of the wagon (16 t) and short overall length (16.44 m) over buffers make it ideal for its intended purpose. By today’s standards, the amount of free space for the lower parts of the semi-trailer is restricted due to the short distance between the bogies and the high wheel blocks and transom. A retractable underride guard and plenty of ground clearance at the rear are compulsory. The earlier design of semi-trailers with large tyre diameters and correspondingly high loading areas made the modifications possible. Nowadays it is no longer feasible to adapt modern, large-volume semi-trailers to the loading space of these types of pocket wagon.
UIC type 1b pocket wagon
The main driving force behind this advanced model was the demand for more payload, which was needed for heavy containers. Type 1a pocket wagons could not be used to move the high loads required due to their small wheels with a diameter of 730 mm. UIC standard bogies with 920 mm wheels were therefore specified for the 1b model. It was important for the cargo space not to be restricted in spite of the bigger bogies, so the distance between the bogie pivots was increased from 11.20 m to 13.30 m. The loading area was lowered from 330 mm to 270 mm above the top edge of the rail thanks to a newly designed base plate. The overall cargo space of the 1b pocket wagon was slightly increased as a result. This did not affect the semi-trailer in any way.
Composite construction pocket wagons
At 17 m and 17.5 t per section, articulated pocket wagons have the advantage of being relatively short and light. The bogie pivot distance of 14.20 m is even larger, providing a long loading area for semi-trailers. The 744 model consists of the pocket wagon section and the carrier section for containers and swap bodies. Kombiverkehr was involved in the development of these pocket wagons.
“T 2000” pocket wagons
“T 2000” pocket wagons are twin-articulated pocket wagons with three bogies and two pockets. This wagon type was developed by Waggonfabrik Talbot and Kombiverkehr in 1996 and purchased in 1997. A new loading concept was implemented with this wagon for the first time: the fixed wheel recess for the last trailer axis no longer determines the loading position of the trailer on the wagon depending on the wheelbase; instead it is the trailer jack, which is nearly always in the same place within a close tolerance. The wheel recess is basically set to take the normal 7.70 m wheelbase. The wheel recess can be adjusted for other wheelbases. This simple measure provides a length of 12.50 m from the trailer jack/semi-trailer coupling pin to the end of the wagon loading area, thus producing the maximum cargo space for pocket wagons so far.
“T 3000” megatrailer pocket wagons
Kombiverkehr has made a substantial contribution to the development of the megatrailer pocket wagon, which is based on the findings of the SAIL (Semi-trailers in Advanced Intermodal Logistics) European Union-funded research project. The megatrailer pocket wagon is the enhanced version of the “T 2000” model, which has become the most popular wagon for the Combined Transport of semi-trailers and swap bodies over the last ten years.
The wagon is a tried-and-tested twin-articulated pocket wagon: a low weight (35 t), shorter wagon length (34 m) and low costs are the advantages of this design. The geometrical design of the cargo area is adapted to the low-lying vehicle parts of megatrailers. The semi-trailer coupling on the wagon has three settings and can be lowered to a height of 113, 98 or 88 centimetres for megatrailers. This is a low semi-mounted height above the loading area, which is only 27 centimetres high, and yet it was possible to opt for bogies with 920 mm wheels on the wagons. The side members of the wagons are lowered in the middle section, thus ensuring that the crane has direct access to the low-lying megatrailer grappler pockets. High-performance buffers to reduce axial force and crash elements in front of and behind the semi-trailer coupling to limit maximum force, which can impact on the trailer’s coupling pin, are some of the features of these wagons. This means there is absolutely no need for wheel blocks in the loading pocket. The pocket wagon is also characterised by a high level of flexibility: as well as megatrailers and conventional cranable trailers, swap bodies up to 7.82 m in length and 20’ containers can also be shipped simply and safely.
Container carriers for the transport of containers and swap bodies
60’ container carrier
60’ container wagons have been tried and tested over many years and are mainly used to transport 20’, 30’ and 40’ containers. With a loading length of 60’, they are ideal for ISO container lengths.
104’ container carrier
104’ articulated container carriers with three bogies are low-cost wagons which are universally suitable for use in heavy volumes of traffic from terminal to terminal. The loading length is designed primarily for 4 x 7.82 m freight containers. Shorter 90’ and 80’ versions are only used for containers measuring between 25’ and 45’.
Low-loader wagons for the transport of complete goods vehicles on the "Rolling Road"
The initial design by Simmerring-Graz-Pauker (SGP): Short eight-axle wagons that were loaded over the coupling point
A goods vehicle drew 1.5 wagons. Special wagons with ballast were required for the transition from the low-lying close coupling to the normal buffer and coupling height.
A design by Waggonfabrik Talbot: Long eight-axle wagons, model DB 690, with a loading area height of 410/450 mm
Each wagon is suitable for the attachment of swivelling buffer beams to facilitate the transition to the normal buffer and coupling height. The loading length is designed to provide enough space for a complete 18.75m goods vehicle.
Another Talbot design: Articulated twelve-axle low-loader wagon with three bogies and a higher payload
The loading area height is likewise 410/450 mm. The same buffer beams can be used with model 690. The wagons are known by the term "Rolling Road transalpine". These wagons are also suitable for the transport of complete goods vehicles.
The low-loader wagons for the "Rolling Road" are rather expensive to purchase and maintain as they have complex special bogies with very small wheels. A straightforward, cost-efficient terminal infrastructure is nevertheless sufficient.