Wallenberg Class
Wallenberg-class tugs are specialized vessels intended to move chains of large cargo modules long distances. A successor design to the Ptolemy-class, it was first designed in the late 2370s, but did not see widespread service until the 2380s. They were notably used during the abortive evacuation of Romulus in the early 2380s. Hundreds of these ships were destroyed during the Synth Attack on Mars in 2385, but hundreds more are still in service as of 2399, in Starfleet and civilian hands. Utilitarian and easy to build, they are essentially a large warp sled with powerful tractor beam emitters.
Overview
While the basic design of the Wallenberg-class existed before the decision to evacuate Romulus, it was modified significantly to make it easier to mass produce. From a distance, the Wallenberg-class is clearly a Federation design, with a primary-secondary hull arrangement, but up close it's clear that many typical features have been omitted for the sake of construction speed, including most windows, all armaments, and other non-critical systems. Indeed, many of these ships weren't painted or even named in the mad rush to build them.
The ship's primary hull is roughly rectangular, with 'wings' flaring out on the aft end that contain the ship's two powerful impulse engines. The bridge module is located in the center of the hull, on a slightly raised superstructure that also contains the majority of the crew quarters. Internally, the primary hull is dominated by the warp core and fuel reserves. Underslung from the primary hull are two massive tractor beam emitters, located in cylinders with forward and aft apertures. These tractor beams are used to move cargo pods in to place under the secondary hull, which contains additional crew quarters and the magnetic latching mechanism that allows the ship to grip its cargo pods. Unlike the older Ptolemy-class, there is no direct umbilical connection between the pods and the ship itself; the pods are entirely self-contained.
In the original design, the primary hull continued all the way to the end of the latching plate, with onboard cargo storage and quarters for passengers. The stock design now dispenses with this, but retains a large docking port on the stern of the primary hull that can be used to attach a module which restores these design functions. Notably, the shuttle bay was omitted in the design used for the Romulan Evacuation, but can be attached here. Most ships of this class on general cargo service have this secondary module installed. Other modules exist, as well, and clever Wallenberg captains have used this docking port to greatly enhance their vessels.
Warp propulsion is provided by two warp nacelles, which straddle the cargo pod. They are capable of propelling the Wallenberg and her attached cargo train at speeds of up to Warp 8. Slow by starship standards, this is is still enormously fast for the sheer mass they are transporting, given that they can pull up to five cargo pods. Unusually, the thin deflector array glows red. Beneath the deflector are six high-gain transporter emitters, which are used to move bulk cargo or large amounts of people.
Onboard accommodations for a crew of eighty are spartan, with everyone except the commanding and first officers sharing at least double quarters. There is, however, a single holodeck, and a crew lounge. A sickbay is present, but often these vessels make due with only an EMH or LMH rather than permanent medical personnel.
Cargo Pods
Wallenberg-class ships are capable of attaching to a wide variety of cargo pods, but the standard model in use is a roughly box-shaped unit with a hexagonal cross-section. These range from bulk cargo to biological transport (i.e. plants and animals) to fluid transport, and are each capable of carrying a massive amount of cargo, equivalent to the total cargo capacity of a cruiser-class starships. Each of these pods has its own fusion reactor or fuel cell, making it independent from the tug, which eliminates the need for a complex umbilical system. They have magnetic connections on their front and rear sections, allowing them to form chains of great length. In-system, chains of 10 or more are not uncommon, but five is the maximum number of pods a Wallenberg-class transport can move at warp speeds.
Colony Pods (Evacuation Pods)
One of the Wallenberg's original purposes was to transport large groups of colonists to settle new worlds, which is one of the reasons they were chosen for the Romulan Evacuation. For colonial missions, they tow specially-built cargo pods that have been equipped for personnel transport. These modules are each capable of carrying two hundred colonists on trips of several weeks. Upon arrival at the colony site, they can detach from the ship and land under their own power. In emergencies, they can also be used as lifeboats, as they have their own power and life support.
There are connections on the bow and stern of these pods that allow people and power to pass between the pods, which allows them to pool their resources for maximum power efficiency. However, like with the cargo pods there is no direct connection between the pods and the ship itself; anyone wishing to move between the two would need to beam over. This was a deliberate design decision, as it helps keep the pods easier to build and it helps keep the crew of the transport insulated from any issues that might arise in the pods.
Each pod has its own sickbay and twenty-four person transporter pad. The sickbay is usually staffed with just an EMH. The transporter can function on its own, or it can use the Wallenberg's primary transporter system as a relay: the Wallenberg has high-powered transporters that can move large amounts of people at once, which is ideal during evacuation missions.
Medical Pods
A variant of the colony pods, medical pods contain patient accommodations for a hundred and can also land on a planet's surface, often as the centerpiece of a field hospital. Generally, a Wallenberg will bring several of these to a disaster site and use them to support dedicated hospital ships, or might carry a train of one medical pod and four colony pods for evacuation missions where wounded are expected.
History
The class was designed in the late 2370s as a replacement for the Federation's aging cargo tugs, especially the Ptolemy-class and its subsequent refit designs. The brief was relatively simple: accomplish cargo towing missions with reliability and endurance. Unlike the Ptolemy, the Wallenberg would accommodate only cargo and colony pods that were self-sustaining, which would streamline construction and minimize the possibilities for component failure. By 2379, several of these starships were already under construction when Starfleet was given the assignment to evacuate Romulus in 2381, under the designation Type-17 Cargo Tug. The design was simplified even further, with half of its superstructure removed (which left the design with the appearance of literally being cut in half) and it was slated for mass production at Utopia Planitia. The class was finally given a name, as well, Wallenberg, after Raoul Wallenberg, a Swedish diplomat who used his influence and immunity to help many Jews escape the Holocaust in German-occupied Hungary during Earth's Second World War.
The existing ships, such as the Nightingale, were also pressed into service here. With a full train of colony pods, a Wallenberg could take a thousand people per trip. It would take 250 of them to move a million people per month (assuming a distance of about 20 light-years to the evacuation site), so Starfleet placed an essentially unlimited order to handle the gargantuan task of evacuating the entire population of Romulus, along with pressing every available ship into service.
These ships moved so rapidly off of the assembly lines that many were not painted or named when they left for Romulus. To speed up production, Starfleet dramatically increased its use of A500 synths at Utopia Planitia, and once production was ramped up, they were leaving the yards at a rate of nearly 25 per week. Between 2381 and 2385, nearly 5,000 of these ships were built, but even a fleet of that size would take nearly 25 years to fully evacuate the planet. Between Romulan military assets and other starships, though, Starfleet was tentatively optimistic that the bulk of the population could be evacuated before the predicted demise of the Romulan sun in 2387 or 2388. A major issue with the evacuation was that the evacuation pods needed to be made again for each trip, as the SCE was having trouble building enough housing at the refugee sites and the life support systems of the pods that weren't consumed in this way needed an overhaul after each mission, anyway. The Wallenberg's engines also needed periodic refits after pulling five pods on extended interstellar trips over and over again, which meant that at any given time, there were more ships in port receiving new pods or repairs as there were ships ready to leave on their first trips.
Disaster struck in 2385, though. On First Contact Day, when the bulk of the Wallenberg-class fleet was at Utopia Planitia, rogue Synths destroyed the shipyards, the entire fleet, and the majority of the planet's surface, which put an instant halt to the evacuation efforts. While there were still several hundred transports off world, they were not nearly enough to complete the evacuation. Indeed, the Federation Council pulled the plug on the entire effort within days of the attack.
The remaining Wallenberg-class ships were either refit to full Starfleet standards and assigned to important strategic cargo routes (such as moving starship parts between shipyards or fuel tanker duties) or passed to civilian agencies and private groups for freight transport duties. While the design is not retired, there are so many still in service that it is not presently being built, as of 2399, and is a favored vessel for colonial transport duties.
The Wallenberg-class In-Play
- This is the transport design seen briefly in Star Trek: Picard. We didn't learn much about them on screen other than they were built in the hundreds (or thousands) and were used to evacuate Romulus in the early 2380s. Enough of them were destroyed to cripple the evacuation, but given the sheer scale of the evacuation (moving 3.5 billion people a thousand at a time takes a while), there must have been others that weren't destroyed.
- These ships would be a good NPC vessel to encounter: a bulk freighter moving a large amount of food or fuel, or a colonial transport. They'd be relatively common, as they are utilitarian, salt-of-the-earth type ships.
- A historical parallel would be the Liberty Ships, which were built en masse during World War II. Any interstellar starship by definition is going to be infinitely more complex than even the most advanced ocean-going ship, but these ships were still built extremely quickly (thanks to synth labor) and they're very basic. It's likely that many in service now are slightly different than their sister ships, using outdated equipment in some places or missing it entirely in others.
- Like all transports, the ones in Starfleet hands would only be used for the most important cargo missions, otherwise it would be handled by civilians. Still, the commanding officer would likely be very junior.