То be + Infinitive is a modal expression. Some of its meanings are close to those of modal verbs and expressions denoting obligation (must, shall, should, ought, to have + Infinitive).

This modal expression can be used in two tenses — the Present Indefinite and the Past Indefinite (was, were).

Dear Jim, I am to be shot at sunrise tomorrow. (Voynich)

They were to go to Spain for the honeymoon. (Galsworthy)

To be + Infinitive expresses a weakened order, an arrangement, possibility, or something thought of as unavoidable. The ways of rendering this expression in Russian differ in accordance with its meaning.

#1. An order which is generally the result of an arrangement made by one person for another, an arrangement that is not to be discussed.

In this case, only the Indefinite Infinitive is used.

You are to go straight to your room. You are to say nothing of this to anyone. (De la Roche)

Schlaghammer frowned. It was not up to him to judge Pettinger… but it was in his province to interpret orders. He was to blast the entrances of the mine. (Heym).

#2. An arrangement, or agreement, part of a plan.

In this meaning both the Indefinite and the Perfect Infinitive can be used; the Perfect Infinitive shows that the action was not carried out.

I’m sorry, Major, we had an agreement — I was to do the questioning here. (Heym)

We were to meet at the entrance of the theatre at a quarter to eight. (mutual arrangement)

“Have you seen him?” Martini asked. “No, he was to have met me here the next morning.” (Voynich)

#3. Possibility.

In this meaning, the passive form of the Infinitive is used unless it is a question beginning with the interrogative adverb how. Here the meaning of the modal expression comes very close to that of the verb can.

For a long time neither was to be seen about their old haunts. (Dreiser)

How are they to know that you are well connected if you do not show it by your costume? (Shaw)

And he knew that higher intellects than those of the Morse circle were to be found in the world. (London)

#4. Something thought of as unavoidable.

Sally wished Morris could be on the same terms of easy friendliness with her as he was with everybody else. But evidently, it was not to be. (Prichard)

I went about brooding over my lot, wondering almost hourly what was to become of me. (Dreiser)