Mr. Ammen's venture into the transport business had become so successful that soon he expanded his fleet to service the other towns of Camarines Sur, Camarines Norte, Albay and Sorsogon. ALATCO became the principal carrier in the Bicol region, inaugurating highway travel that was to open remote villages in the Bicolandia, to the mainstream of economic and social development.

The War in 1942 aborted expansion of the transport company. When it resumed operations in 1945 with surplus US Navy trucks bought from the United States Commercial Company, the company was faced with ruinous competition and beset with problems of maintaining its efficiency and safety as a result of her expanded size and nature of operations.

The Heirs of Don Nicasio Tuazon of Manila took over ownership of ALATCO in 1949 and, with infusion of new capital, embarked on an ambitious program of expansion and rehabilitation. One important development at this time was the company's "dieselization" Program that converted its gas-powered trucks to diesel.

In 1952, there were already 400 units in the ALATCO fleet. ALATCO centered its fleet in Iriga but also maintained subsidiary shops in Daet, Camarines Norte, Naga City, Camarines Sur, Ligao, Tabaco and Legaspi in Albay and Sorsogon and Irosin in Sorsogon.

In 1953, the company ventured to Quezon province by consolidating into local and express bus operations three small bus companies servicing the area. Operating under the umbrella of the Eastern Tayabas Bus Co. (ETBCO) headed by Sr. Ramón Soler. EBTCO later entered into a 5-year lease contract with the Laguna Tayabas Bus Company (LTBCO).

In 1971, the two companies were sold to the Mantrade Group that formally amalgamated the operations of the two firms into one company. It was named the Pantranco South Express, Inc. (PSEI) to differentiate it from its northern counterpart, which the group then already owned.

In 1973, compounded by global crises and steep escalation of fuel costs, PSEI nearly collapsed. The new owners and manager (the Lopa-Coujuangco group) insisted on providing the service even during floods, road interruptions and bad road conditions. Debt-strapped and traumatized by high operations cost, the company's creditors decided to take over the organization.

In 1974, the Creditors Syndicate of PSEI decided to develop and implement a Corporate Rehabilitation Program. The same year, the Company added Catanduanes, Samar and Masbate to its scope of operations, having formalized tie-ups with passenger ferry operators in these areas.

In 1978, PSEI introduced its air-conditioned coaches in its Southern route.

In 1980, the Company expanded its freight service operations and moved its Central offices and terminal at its present site in Pasay City.

The Company pioneered in Eastern Visayas in 1981 and by year-end had connected all of Leyte and Samar provinces to the Luzon mainstream.

PSEI also entered the sea transport business with its passenger and vehicle ferry, linking the ports of Matnog, Sorsogon and Allen, Northern Samar.

A new level of service was inaugurated in 1982 with the addition of Royal Class and new air-conditioned coaches with toilets and VCR's in the company's fleet. PSEI also became the first bus company in the Philippines to computerize its operations in 1982.

In 1984, PSEI together with two other ferryboat operators, formed a joint venture company, the St. Bernard Services Corp. (SBTC) that now operates in the San Bernardino Strait, the government ferry boat, Maharlika I. In the same year, the company changed its name to Philtranco Service Enterprises. Inc.

In 1986 commemorated its Luzon-Visayas-Mindanao (LUZVIMINDA) run which was the first trans-Philippine bus-cum-ferry-operations. Now PSEI has seven ferryboat operations.

Having opened the southern frontiers of Mindanao to Luzon and Visayas with its intermodal transport service, Philtranco hopes to contribute its share in effecting the real unification of the nation where the economic, educational, cultural, political and social opportunities are shared by every Filipino.

In April 1999, Penta Pacific Realty Corporation acquired PSEI headed by businessman Jose CH. Alvarez. This new group immediately programmed a fleet replacement of 80 units costing 250 million pesos.

The 29-seater Gold Service Bus was introduced on June 2000 initially serving key cities in the Bicol region, having a coach stewardess as an additional crew to assist passengers, giving the same service as that of an airline.

On June 1, 2001, PSEI implemented the Passenger Check-in and Baggage Tag System procedures for the security, convenience and comfort of our riding public. PSEI is the first Bus Company to adopt this kind of procedure patterned after the airline system. Today, Philtranco is a symbol of progress in the Philippine transport industry. The Company continues to blaze new trails with the innovations in its levels and brands of services.