PMT Timeline & Overview

The following PMT timeline was provided by Jim Eager compiled from various news and feature items published in Railway Age and other sources:

1953 -- SP begins piggyback operations carrying lcl/ltl freight in SPT and PMT vans on converted 40ft & 52ft flats, and soon after adds full truck-load service. T&NO Houston-Lake Charles, LA service started first in May, then Los Angeles-San Francisco in California in July, with traffic handled by the Overnight trains at first, then by Advance Overnight solid tofc trains. Los Angels-Phoenix service added later.

1954 -- Service extended to Houston-Dallas/Fort Worth, Nevada, plus Idaho, Utah, Wyoming interline via UP; SSW begins trailer-load service in Sept using converted flats and SWT trailers.

1955 -- Service extended to Ukia & Portland, OR, and to Seattle, WA via NP; some interline traffic with SSW, GN, NP; SP moves 37,736 trailers in first 9 months. PMT orders first 35ft vans. Piggyback pool eventually includes ordinary dry and insulated vans, mech reefers, some with meat rails, open-tops, and flatbeds with and without removable sides; trailers built by American, Brown, Fruehauf, Hobbs, Lufkin, Strick, Trailmobile and Utility, among others. PMT uses a trailer hitch system without a kingpin, which inhibits interchange of equipment; uses stanchions and tie-downs on flat cars; never adopts ACF's Model A collapsable hitch, which requires a trailer kingpin.

1957 -- SP puts first F-50-17 79ft Clejan tofc flat in service; Clejan system offered efficient loading and unloading but was incompatible with most connecting railroads and shipper and common carrier trucks without laborious modifications to each trailer; tests containers on Clejan cars. SP participates in two of the first trascontinental interline tofc movements: a printing press shipped from Hoboken to Santa Anna via DL&W-NKP-SSW-T&NO-SP, and a pharmaceutical shipment via DL&W-NKP-SSW-T&NO-SP; begins common- carrier service between Los Angeles-San Francisco-Portland with three western common carrier truck lines. [Which ones is not specified.]

1958 -- SP orders F-70-14 85ft Clejan flats from GATC; establishes interline service to Seattle and Tacoma via NP [redundant report?], and Chicago-Oakland via RI-D&RGW for common carrier Plan I traffic of Consolidated Freightways, which sparks court challenge by Teamsters union; tests auto carrier trailers in TOFC service in conjunction with GM.

1959 -- SSW & PFE get conventional 85ft ACF pig flats with ACF hitches; SSW joins Trailer Train; regular TOFC shipment of new automobiles using semi-trailer auto carriers begun by SP and numerous other railroads

1960 -- SP puts first dual conventional and Clajen-capable 85ft G85s in service; SP joins Trailer Train, begins handling conventional interline tofc traffic from connecting roads

1965-66 -- Trailing Z added to unit reporting marks (PMT/SPT/SWT to PMTZ/SPTZ/SWTZ) and existing piggyback trailers are renumbered to comply with the AAR 6-digit number system; required two digit length/ type prefix added to existing unit number at first, until fleet can be completely renumbered. Begins using SPLZ reporting mark for non- PMT/SPT trailers leased specifically for piggyback service, and RSPL for vans leased from REA Leasing (Realco)

1970 -- Last new PMTZ, SPTZ, SWTZ marked piggyback trailers added to Equipment Registers; all subsequent additions marked SPLZ, RSPZ or XSPZ (leased from Xtra Inc.)

1981-82 -- SP acquires it's first 45ft Golden Pig Service vans for piggyback service, SPLZ 250000-250299.


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