EXHIBIT 21

TRINITY INDUSTRIES, INC.

Listing of Subsidiaries of the Registrant

The Registrant has no parent.

At May 19, 2004, the operating subsidiaries of the Registrant were:

					Percentage of
					voting securities
					owned by the
Name of subsidiary				Organized in	Registrant
Apromat, S.A. — Arad				Romania		50%
Astra Vagoane, S.A. — Arad				Romania		96%
ICPV, S.A. — Arad				Romania		89%
International Industrial Indemnity Co.				Vermont		100%
Reunion General Agency, Inc.				Texas		100%
Syro, Inc.				Ohio		100%
Transit Mix Concrete & Materials Company				Delaware		100%
	Transit Mix Concrete — Baytown, Inc.			Texas		100%
	Transit Mix Transportation Services, LLC			Delaware		100%
Transit Mix Concrete & Materials Co. of Louisiana				Delaware		100%
Trinity Argentina S.R.L				Argentina		100%
Trinity EE, Inc.				Delaware		100%
Trinity Equipment Company, Inc.				Delaware		100%
Trinity Fittings Group, Inc.				Delaware		100%
Trinity Industries Buffalo, Inc.				Delaware		100%
Trinity Industries International, Inc.				Delaware		100%
Trinity Industries International Holdings AG				Switzerland		100%
	Administradora Especializada, S. de R.L. de C.V.			Mexico		100%
	Grupo Tatsa, S. de R.L. de C.V.			Mexico		100%
		Trinity Industries de Mexico, S. de R.L. de C.V.		Mexico		100%
	Servicios Corporativos Tatsa, S. de R.L. de C.V.			Mexico		100%
	Trinity Industries do Brasil, Ltda.			Brazil		100%
	Trinity Industries GmbH			Switzerland		100%
		Wagonmarket, spol. S.r.o		Slovak Republic		100%
	Trinity Rail do Brasil, Ltda.			Brazil		100%
Trinity Industries Leasing Company				Delaware		100%
	Transport Capital, LLC			Delaware		100%
	Trinity Financial Services, Inc.			Delaware		100%
	Trinity Marks Company			Texas		100%
	TILX GP II, LLC			Delaware		100%
		Trinity Rail Leasing II, L.P.		Delaware		1%
	TILX LP II, LLC			Delaware		100%
		Trinity Rail Leasing II, L.P.		Delaware		99%
			Trinity Rail Leasing Trust II	Delaware		100%
	TILX GP III, LLC			Delaware		100%
		Trinity Rail Leasing III, L.P.		Texas		1%
	TILX LP III, LLC			Texas		100%
		Trinity Rail Leasing III, L.P.		Texas		99%
	TILC Equity OP GP III-C, LLC			Delaware		100%
		TILC Equity OP III-C, L.P.		Texas		1%
	TILC Equity OP LP III-C, LLC			Delaware		100%
		TILC Equity OP III-C, L.P.		Texas		99%
	Trinity Marine Leasing, Inc.			Delaware		100%
Trinity Industries Real Properties, Inc.				Delaware		100%
Trinity Industries Transportation, Inc.				Texas		100%
	Trinity Industries Transportation Services, LLC			Delaware		100%
Trinity Marine Products, Inc.				Delaware		100%
Trinity Materials, Inc.				Delaware		100%
Trinity Mining Services, Inc.				Delaware		100%

						Percentage of
						voting securities
						owned by the
Name of subsidiary					Organized in	Registrant
Trinity Rail Group, LLC					Delaware		100%
	Thrall Vagonka Studenka, a.s				Czech Republic		95%
	Thrall International Holdings LLC				Illinois		99%
		Thrall Europa			Eng. & Wales		100%
	Thrall Company				Delaware		100%
		Rail Project, s.r.o			Slovak Republic		100%
	Thrall Trinity Freight Car, Inc.				Delaware		100%
		DIFCO, Inc.			Ohio		100%
	Trinity Rail Components & Repair, Inc.				Delaware		100%
		McConway and Torley Corporation			Pennsylvania		100%
			MCT Properties, Inc.		Delaware		100%
			McConway and Torley — Anniston, Inc.		Delaware		100%
		Standard Forged Products, Inc.			Delaware		100%
		Trinity Railcar Repair, Inc.			Delaware		100%
	Trinity Rail GmbH				Switzerland		100%
	Trinity Tank Car, Inc.				Delaware		100%
Trinity Rail, Inc.					Delaware		100%
	Trinity Rail Management, Inc.				Delaware		100%
		TILX GP I, LLC			Delaware		100%
				Trinity Rail Leasing I, L.P.	Texas		1%
		TILX LP I, LLC			Delaware		100%
				Trinity Rail Leasing I, L.P.	Texas		99%
Trinity Rail Market Services, Inc.					Delaware		100%
Trinity Structural Towers, Inc.					Delaware		100%
TRN Investment Company, Inc.					Delaware		100%
	TRN, Inc.				Delaware		100%